“Knowledge is knowing that a tomato is a fruit and wisdom is knowing not to put it in the fruit salad.”

Pastry Chef April Robinson, owner of Ritual Bakehouse in Brunswick, quoted that expression to me when I called her to chat about the idea of using tomatoes in dessert. I wasn’t dissuaded — nor was she. She’s baked with tomatoes herself, combining them with rhubarb (in a tart), with melons (topped with a crumble and granita), with roasted balsamic strawberries and with nectarines.

So can tomatoes swing both ways? Most of our associations are on the savory side, of course — sauce, pizza, ketchup, soup (or as pastry chef Kate Hamm, co-owner of Fish & Whistle in Biddeford summed it up, “pasta, pasta, pizza”). But as a curious hobby baker who has added carrots, beets, zucchini and parsnips to her cakes for decades, I wondered why the heck not?

Hear me out:

• Tomatoes are pretty and come in many colors, enticement enough for a baker. Add to that, during local tomato season, tomatoes are often described as tasting sweet.

• When it comes to unripe tomatoes, bakers have long recognized that tomatoes are, botanically speaking, a fruit. Case in point: old-fashioned green tomato pie.

• Speaking of vintage recipes, raise your hand if you remember Tomato Soup Cake. Sure, it was a gimmick 100 years ago from the Campbell’s Soup Company, but so what? It makes a good, homey cake.

• “Tomato season is incredible,” Robinson said. “It’s what everybody looks forward to in summertime.” I say, spread the love to the last course.

• In the last 15 years, we Americans have been incorporating seemingly oddball savory ingredients into dessert with abandon, adding chopped, candied bacon to cookies and chocolate bars; tahini and miso to cakes and cookies; and hefty pinches of sea salt to caramel and the tops of cookies. As Hamm mused after we batted the tomatoes-for-dessert idea around, “I wonder if it will maybe be the next thing?”

“Using them in dessert?” Brant Dadaleares, owner of Gross Confection Bar in Portland, repeated the question before answering it. “Absolutely!”

But the proof is in the pudding, or in the cake, cookie or ice cream, as the case may be.

ORIGIN STORY

Did world-famous Chef Alain Passard invent the idea of giving tomatoes the dessert treatment at his three-Michelin-starred restaurant L’Arpege in Paris in the 1980s? Robinson described her excitement as a young pastry chef when she first read about Passard’s legendary whole tomato braised in caramel and stuffed with fresh fruit and spices (Tomate Confit aux Douze Saveurs), a dessert that went viral before going viral existed.

I first encountered the idea in 2001, in Claudia Fleming’s “The Last Course: The Desserts of Gramercy Tavern,” which includes an easy recipe for Sauté of Tomatoes and Plums. “Make sure to use sweet, ripe tomatoes, preferably a mix of heirloom varieties for the most gorgeous array of textures and colors,” she advised. (Hamm reiterated this when asked for advice about baking with tomatoes. “You just need to make sure you have a really ripe, really good tomato,” she said. Supermarket tomatoes, she added, are not going to cut it.)

Dadaleares, a Fore Street alum who has made tomato sorbet with basil granita, credits founding Fore Street chef Sam Hayward for the inspiration. “He really taught me about the importance of understanding the ingredients which you’re working with and how to utilize them and what pairs with them well,” Dadaleares said. “He’s definitely a driving force for me to think about sweet and savory together.”

For her part, Hamm was sparked by Robinson, her friend, who’d mentioned to her the idea of combining peaches and tomatoes. For a special harvest dinner at the late Tao Yuan in Brunswick in 2017, “I ended up going with that, and that is a great combination,” she said. “The peaches mimic the lush meatiness of the tomato but steer it into the the realm of the sweet. And they’re so good together.”

What exactly did she make? Hamm can’t recall, but “I do remember it being delicious.”

And recently, the Chinese snack tanghulu has taken TikTok by storm. To make it, fruit on skewers — including cherry tomatoes — are dipped in melted sugar and candied to a satisfying crunch.

Still, the concept of tomatoes as a sweet has mostly not reached the mainstream. Checking the indices of my 70 or so baking books yielded just that single tomatoes-plums recipe. Even the Italians, a nation of tomato lovers, seem not to have exploited them for dessert. In “Dolce Italiano,” Gina DePalma’s 300-page book of desserts from Babbo restaurant in New York, nary a tomato lurks among the strufoli, the sbrisolona and the zabaione.

TOUGH SELL?

Hamm doesn’t remember ever baking her peach-tomato dessert again. The harvest dinner had a set menu, “so the dessert is included and no one gets to choose,” she explained. “If you’re selling a dessert in a restaurant, even if it’s good, it can be a tough sell. It’s always kind of working against people’s associations.”

Echoed Dadaleares, “Most people, if you’re going to step into the grounds of putting tomatoes into dessert, they’re going to be like, ‘What the f— are you talking about? That sounds odd.’ ”

His response to the doubters? “Trust me. We’ve been doing this for a while. Just trust what we have in mind.”

My co-workers were surprisingly trusting when I brought a tomato-cornmeal upside down cake into the office in July. Feedback ranged from heart and tomato emojis to a heartfelt “I love it” (followed, disappointingly, by “but I have no standards”) to a detailed analysis praising “excellent flavor” but questioning “a bit of a textural disconnect between the coarse cornmeal base and the very smooth texture of the tomatoes.”

I mentioned that cake to Atsuko Fujimoto, James Beard award-winning pastry chef at Norimoto, who was, it must be said, slightly skeptical of swapping in tomatoes where fruits like plums, pears and apricots are the norm. “I would try it. I’m usually up for it,” she said. “But why? Why tomato? I do feel like, yeah, it better be good.”

Even AI seems to reject the idea of tomatoes for dessert. I regularly use an AI system to transcribe interview tapes, but it resolutely refused to recognize the phrase “tomato soft serve” ice cream, transcribing it three times as “tomato sauce” and once as “tomato soup,” as if it JUST COULD NOT BELIEVE WHAT IT WAS HEARING.

ANATOMY OF A DESSERT

Pastry Chef Ilma Lopez, who co-owns Chaval and The Ugly Duckling, both in Portland, has never shied away from eye-opening desserts. She’s been making serrano ham ice cream at Chaval since at least 2017, originally as part of a Spanish sundae, these days served with bourbon bittersweet chocolate tart and orange caramel. In the spring, Chaval features white asparagus and caviar ice cream. And on the restaurant’s menu now, while the season lasts, is a vanilla jelly roll cake filled with tomato jam and cream cheese, and topped with sherry ice cream and tomato granita.

She created the recipe both to solve a problem and to translate her favorite Spanish breakfast into a cake. “We go through a lot of tomatoes,” Lopez said, many of them for Chaval’s popular pan con tomate, a Catalan tapa made from toasted bread, garlic, tomatoes and olive oil. “One of the biggest byproducts of our tomato bread is tomato water,” she said. She conceived the cake in part as a way to use it up. (The restaurant also uses the tomato water in a bright, refreshing tomato daiquiri.)

Lopez loves tomatoes and she especially adores a “super famous” Spanish breakfast of a toasted baguette slathered with tomato jam. She likes how Spaniards serve “tomato jam with everything,” she said. “I love tomato jam and cheese.”

So she filled her jelly roll cake with tomato jam and topped it with a granita made from the excess tomato water. She edges the cake in caramel and then brulees it and garnishes each slice with bright golden, edible marigolds from her garden. The dessert is simultaneously homey and sophisticated, light yet rich, creamy and very slightly crunchy and altogether summery. It’s a winner.

Lopez explained her dessert philosophy: If you are going to challenge eaters, she said, you need to give them familiar elements, too. Reel them in with jelly roll cake and ice cream, in other words, and then astound and amaze them with tomato jam and tomato granita.

A GIANT TOMATO ICE CUBE

If you’re a fan of Fujimoto’s Norimoto Bakery in Deering Center, you’ll recognize that feeling as it describes many of her wonderfully unorthodox combinations, for instance, her suggestion for a tomato dessert.

“My favorite way is to freeze the whole tomato, a whole very ripe tomato,” she said. “You’re making a giant tomato ice cube and then you just shave the whole thing. Shaved tomato ice. You put this shaved tomato over vanilla ice cream. It’s just so great because you want something cold when…,” her voice trailed off. “In tomato season, obviously it’s hot out and the last thing you want to do is to bake, to turn your oven on.”

Fujimoto said she doesn’t bother to peel or deseed the tomato beforehand, though I did peel my farmers market tomato before freezing it. I struggled a little to grate it on a box grater, but it worked more easily once I took Fujimoto’s advice and switched to a mandolin. I drizzled the bowl of ice cream and tomato granita with a good, fruity olive oil and sprinkled it with sea salt. It made a dessert that was more than the sum of its parts: delicious, surprising and almost effortless.

There’s another ice cream I hope to try soon. When Hamm and I exchanged ideas about tomatoes in desserts, I asked her if she’d ever attempted tomato ice cream?

“Honestly, now you have me thinking about tomato soft serve, which I wouldn’t have come up on my own but may be really delicious,” she said. “Sometimes I’ll do a wacky flavor and it will just sit, and then sometimes I’ll do a wacky flavor and it will be the most popular flavor that we’ve ever done. It’s like trying to catch a wave.”

Still not sold? You’d still rather walk on the savory side? Alternatively, Fujimoto suggests shaving her big tomato ice cube over cold soba noodles for a refreshing summer meal. And she happened to mention that tomato leaves are edible — I’m gobsmacked — and you can use them as an herb.

But that’s a whole other story.

ROSEMARY COOKIES WITH TOMATO JAM

This recipe comes from David Lebovitz’s “Ready for Dessert.” I’m not surprised to find a former pastry chef from Chez Panisse experimenting with seasonal produce. He writes that the recipe was inspired in a roundabout way, beginning with an unusual dessert he tasted at an Italian restaurant of ricotta-stuffed eggplant with candied orange and chocolate sauce. “I do believe in giving a chance to things that are out of the ordinary, otherwise, how would we discover new flavors and tastes?” he writes in the recipe note. The cookies are terrific.

Makes about 24 cookies, per Lebovitz. I got 36 cookies.

2 cups all-purpose flour

1/4 cup stone-ground yellow cornmeal or polenta

1/2 teaspoon salt

1 cup unsalted butter, at room temperature

10 tablespoons sugar

2 large egg yolks

1 ½ tablespoons finely chopped rosemary leaves

Tomato jam (see recipe)

In a small bowl, whisk together the flour, cornmeal and salt.

In a stand mixer, beat together the butter and sugar on medium speed until just smooth. Mix in the egg yolks, then the rosemary. Add the flour mixture and mix until the dough is smooth and holds together.

On a lightly floured work surface, divide the dough in half. Shape each half into a log about 6 inches long and 1¾ inches in diameter. Wrap the logs in plastic wrap and refrigerate until chilled and firm, at least 1 hour.

Preheat the oven to 350 degrees F. Line 2 baking sheets with parchment paper or silicone baking mats.

Slice the chilled logs into disks 1/4 inch thick and place the disks about 1/2 inch apart on the prepared baking sheets.

Bake, rotating the baking sheets midway through baking until the edges of the cookies are lightly browned, about 12 minutes. Let cool completely.

Spread a scant 1 ½ teaspoons of the jam on the underside of half the cookies. Top the jam with a second cookie, bottom side down, to make sandwiches.

Once filled, the cookies can be stored in an airtight container for up to 3 days.

TOMATO JAM

Slightly adapted from David Lebovitz’s “Ready for Dessert.” You won’t need all of it to make the cookies. He also likes the jam to accompany cheese. I followed his suggestion with the leftovers, spreading toast with the jam and topping it with a slice of feta cheese. Excellent!

Yield: 2 cups

2 ¼ pounds ripe tomatoes (about 5 large)

2 ¼ cups sugar

2 to 5 grinds of black pepper

Big pinch of salt

Zest from 1/2 lemon and 1 teaspoon (or more to taste) freshly squeezed lemon juice

To peel the tomatoes, bring a large saucepan of water to a boil. Make a shallow X in the bottom of each tomato with a paring knife. Plunge the tomatoes into the boiling water for about 30 seconds, at which point their skins should loosen. Remove the tomatoes with a slotted spoon. Let cool. Slip off and discard the skins and the hot water.

Halve the tomatoes across their equator and gently squeeze out the seeds and juice. (I strain this and add it back in to the cooking jam.) Chop the tomatoes into 1/2-inch pieces. Put the pieces into the now empty pot with the sugar, pepper, salt and strained tomato water.

Cook over medium heat, stirring frequently, and skimming off any foam, until most of the liquid has cooked off and it passes the freezer plate test: Stick a plate in the freezer. When you think the jam is ready, put a dab on the plate and run your spoon through it. If it holds, it doesn’t immediately fill in, the jam is ready.  This may take longer than you think. Remove the jam from the heat and stir in the lemon zest and juice.

Ladle the jam into clean jars. Let cool. Cover and refrigerate. The jam will keep for at least six months in the refrigerator.