Basil Pecan Pesto for Maine Course Credit: Sarah Walker Caron / BDN

Classic basil pesto is perfect on its own. But there’s also a world of pestos beyond the basil-based classic.

At its most basic, pesto is a crushed combination of basil, olive oil, garlic, pine nuts, salt, pepper and a touch of parmesan cheese. Once you have that basic recipe down, it offers room for variation in several of the central ingredients.

Sandy Oliver, food historian and columnist for the Bangor Daily News, said that while basil pesto is delicious, whatever pesto she makes is ultimately a response to what is ready in her garden.

“The word pesto is actually past tense in Italian for pestare, which means to crush,” Oliver said. “When you understand that then you start looking around at green things and start thinking what can be crushed here.”

Switch out the basil

Perhaps the most obvious swap for basil is other herbs. For example, parsley makes for a delicious pesto.

“Parsley is probably my all time favorite herb,” said Rob Dumas, food science innovation coordinator at the University of Maine. “It’s super hardy and it grows spring through winter without trying to bolt or flower. It’s very good for you, it stays delicious all the time [and] it makes a wonderful pesto kind of thing.”

Cilantro pesto is another option, which would work well with Asian and Mexican cuisine.

“Use sliced ginger root instead of garlic, unsalted cashews instead of pine nuts,” said Lorel Nazzaro, Brunswick-based author of “The Pesto Manifesto.” “[It’s] good over rice noodles with a sprinkle of unsweetened coconut flakes.”

You can also mix basil with these other ingredients — anything you have in the kitchen, really — to make a mixed pesto. Nazarro said that a pesto with a combination of basil and mint, which are in the same family, makes a wonderful sauce for steamed veggies such as zucchini, peas or green beans.

Other herbs that Oliver likes to use include dill and tarragon — but, she noted that not all herbs work in a pesto.

“I don’t mess around with any of the savories,” Oliver said. “I don’t do an oregano one.”

Certain leafy greens can also be used as a substitute for basil for pesto.

Kale pesto is also delicious, but you have to make sure you remove the tough ribs before crushing it, and tougher leafy greens might also benefit from blanching. Nazarro said that arugula pesto, with its slight spiciness, is especially good on pizza.

Kale pesto is a great way to use leftover kale up. Credit: Courtesy of Sandy Oliver

“Submerge it in boiling salted water until tender, then put it in ice water,” Dumas said. “That sets chlorophyll in bright green whereas if you were to blend straight up get an Army green.”

You can also use greens that you would normally toss, like beet greens or carrot tops.

“You substitute carrot tops for the basil component or you can add basil with it,” said Mary Margaret Ripley, co-owner of Ripley Farm in Dover-Foxcroft. “That’s a cool way to use up something from your garden that you might not otherwise use.”

Also, pay attention to unique seasonal treats. Dumas said that he makes a pesto from ramps every year when they are in season. Garlic  scapes in place of basil will make for an extra-garlicky pesto, though like with kale, the tough parts need to be removed. Oliver said to remove the part that “looks like a beak” near the flower head, and then bounce your knife along the scape to find where the tender parts begin (the knife will easily cut through).

Garlic Scape Pesto. Credit: Fia Fortune / BDN

Switch out other ingredients

You can also make other swaps in pesto. For example, pine nuts, which are often expensive (and, Dumas said, often go rancid at the grocery store, where they are left on shelves too long) can be swapped out for other fatty nuts. Oliver said that walnuts and pecans are ideal swaps for pesto because they are fatty and hold the flavor.

For vegan pesto, you can skip cheese altogether, or replace it with nutritional yeast.

“It adds a big umami hit and is actually pretty yummy stuff, even for non-vegans,” Dumas said.

If you are feeling really experimental, you can even swap out your olive oil for other fats. Oliver said that she remembers famed chef Julia Child making pesto with a slab of pork fat instead of olive oil.

“She put that in her pestle and pounded the daylight out of it,” Oliver said. “You take all these concepts of crushing and fat and you can play with it.”

Regardless of what you use, Nazarro said to make sure that you don’t over-process your pesto.

“In Italy they say you should have ‘dente verde’ after eating pesto [or] green teeth, meaning there should be little bits of basil in the pesto,” Nazarro said. “You don’t want your pesto to come out like baby food.”

Dumas said that there is a distinct advantage to using a mortar and pestle for this reason.

“The way that a mortar and pestle works with the grinding motion and the coarseness of the bowl agitating it you end up with a smoother emulsion than you would in a food processor or blender,” Dumas said. “You also don’t have as much heat generated with a mortar and pestle as you would a high speed blender. Emulsions are what you’re making in a good pesto.”

A food processor will work well, though, if you are looking to be efficient or don’t have a mortar and pestle.

Using and storing pesto

Once you make pesto, you can use it in a variety of ways. Oliver recommended adding pesto to mayonnaise for sandwiches, or to ricotta to use for an extra-flavorful lasagna. Ripley said that she likes to put pesto in sour cream or yogurt to make a dip.

“You can use pesto in or on anything to which you might add garlic, such as soups, cheese biscuits [and] egg dishes,” Nazarro said. “Or baste any kind of meat or veggie, even hot dogs, corn on the cob, before grilling. My favorite is to marinate sea scallops in pesto with a bit of lemon or lime juice. Then grill over hot coals to sear them and seal in the juices. You can also do this with cooked, shelled lobster tail meat.”

Dumas said that pesto can also be mixed with butter to be used as compound butter. A slab of pesto compound butter melted on top of a hot steak, he said, will instantly elevate the meal.

Pesto can be stored for several weeks in the refrigerator. Ripley said that putting a layer of oil on top of the pesto and digging underneath it when you want to use the sauce will prevent it from oxidizing into an unpleasant color. Adding a splash of lemon juice or vinegar will also help stave off oxidization.

Pesto can also be frozen (though Nazarro noted that if you do so, you should keep the cheese out and add it when you are using it, as it will freeze better that way).

“Some people get really slick and have dedicated ice cube trays, pop out a block and thaw it out to add into something like a hummus or pasta or marinade,” Dumas said. “It’s an incredibly versatile ingredient [that] adds a pop of summer harvest into cooking all year long. It’s totally ok to make your own kind of version of a pesto with what you have available to you.”