There are few days when I don’t have time to talk about food with anyone who happens to ask. At the dentist’s office last week, I put down the mind candy People magazine was offering to chat with the receptionist about pesto.

“It says on the label not to heat it up. Can I bake with it? It’s kind of expensive and I don’t want to waste it,” she said.

The short answer: certainly. The warning was likely meant to stop cooks from simmering the commercial paste in a saucepan, a process that would turn the basil black and the cheese clumpy and erase the pesto’s bright, summery taste. Those conditions don’t apply if pesto is one of the layers in your summer vegetable lasagna.

You can control for basil oxidation and cheese congealment if you make your own, I continued. You can blanch the basil or mix it with parsley to keep the color vibrant and you can hold back on the cheese until you’re sure the pesto is bound for the pasta bowl.

Can you give me a recipe? I could, but it’s more sustainable to think of making pesto as a ratio-based operation so you can create as many dishes as you’d like with the ingredients you have on hand (or need to use up) at any given time.

Most people think of pesto as the classic Genovese combination of basil, pine nuts, garlic, olive oil and grated cheese traditionally pounded to a paste with a mortar and pestle. But in truth, it’s just a means by which you can preserve the fresh herbs abundant at this time of year with a variety of other ingredients into a mixture that can be tossed with everything from agnolotti to ziti and slathered on anything from crusty bread to grilled crustaceans.

Ratios are generally expressed with the largest quantity first and move on down the line. Recipe ingredient lists are generally written in the order in which they are used in the recipe first, and according to descending quantities second. So this ratio recipes pulls a bit from both structures and goes something like this: 3 cups to up to 1 cup; to 1/3 cup; to 1 garlic clove; to 1/2 cup; to 1/2 cup; to taste. Easy as paste, I say.

The first component is always going to be the herbs (basil, cilantro, mint, oregano, parsley, thyme) and greens (arugula, beet greens, chard, kale, mustard greens, spinach) in some combination. You’ll need 3 loosely packed cups altogether of these.

Many pestos contain a secondary flavor component – mainly a sweeter one like corn, peas, roasted red peppers or sun-dried tomatoes. I hold these elements to 1 cup to keep fresh herbs as the stars.

Next, the nuts. Pignoli (the Italian word for pine nuts) are traditional, but expensive because it’s a pretty arduous process to take the seeds from the pine cone and then shell them. While no nut is wholly sustainable given their water requirements and travel times to Maine, walnuts, pistachios, almonds and pecans as well as some seeds like pepitas and sunflowers work well in pesto, too. You’ll need 1/3cup. Toasting releases their oils, thereby boosting the flavor for a relatively small volume.

The pungency of pesto comes from the garlic, but how strong your clove is will vary. I start with 1 large one and move up as I need to, but I rarely do.

All of these ingredients get mashed together (using a mortar and pestle if you’ve got a big one or a food processor if you don’t), before 1/2 cup oil – traditionally olive oil if your herbs are strong but you can use more neutral ones if your herbs are more timid – gets processed in next.

You taste the pesto at this juncture, adding lemon zest and juice to lighten its taste if necessary and a pinch of cayenne if it needs heat.

Only add the cheese – 1/2 cup of a grated hard one – if you are going to put the pesto in the refrigerator and use it up within a few days. If you plan to freeze it – and you can do so for up to six months – it’s best to do so without the cheese; ice cube trays are great for this job. Add 1 tablespoon of cheese to every cube of thawed pesto when you use it, whenever that may be.

Christine Burns Rudalevige is a food writer, a recipe developer and tester, and a cooking teacher in Brunswick. Contact her at: [email protected].

Cilantro-and-Corn Pesto Fish Tacos

If you are one of those people who think cilantro tastes like soap but are still reading this recipe because it sounds interesting, substitute parsley and add more lime juice to the mix. I’ve made this as many times in my Mexican molcajete (mortar) and tejolete (pestle) as I’ve made it my food processor. Toss the extra pesto with raw zucchini ribbons, cooked fettucine and 1/4 cup of pasta water for a second meal. The recipe calls for corn flour, which is very finely milled cornmeal. If you are lucky enough to get your hands on thinner corn tortillas, you might want to use a double layer for each taco as sometimes a single one will give way in your hand.

Serves 4 (with some leftover pesto)

2 cup loosely packed spinach leaves
1 cup loosely packed cilantro leaves
1 cup fresh corn kernels
1/3 cup toasted pepitas 1 garlic clove
1/2 cup neutral oil, such as grapeseed or canola, plus more for cooking fish
1 teaspoon lime zest and 1 teaspoon lime juice
Salt
Cayenne pepper
1/2 cup finely grated hard cheese (Dry Jack is great)
1/4 cup rice or corn flour
11/2 pounds flaky white fish fillets, cut into about 4-inch pieces
8 small corn or flour tortillas, warmed
1 cup thinly sliced purple cabbage
Lime wedges for serving

Combine spinach, cilantro, corn, pepitas and garlic in the bowl of a food processor. Pulse until the mixture is a fine paste. With the machine running, slowly pour
in the oil until it is fully incorporated. Stir in lime zest and juice.  Add salt and cayenne to taste. Stir in cheese. Set pesto aside.

Combine flour with 1/2 teaspoon salt and 1/4 teaspoon cayenne on a plate. Dredge fish pieces on all sides in the seasoned flour. Set aside.

Add 2 tablespoons of oil to a 12-inch frying pan to skim-coat the pan. Place the pan over high heat until the oil shimmers. Turn down the heat to medium high and arrange the pieces of fish in the hot oil. Fry the
fish until it is slightly browned on one side, about 4 minutes, flip the pieces and cook until they are opaque at their centers, about 2 minutes more for thinner flounder, haddock and redfish fillets or 4 minutes for thicker pollock, hake or cod fillets. Set the fish on paper bags to drain.

To build the tacos, slather each tortilla with 2 tablespoons of pesto, top with 1/8 of the fish, a tablespoon or so of cabbage and a lime wedge.

Serve immediately.