06 May Nasturtium pesto: A quick and easy recipe

2023 UPDATE: Pine nut harvesting can have a severe environmental impact. So, in this recipe, we replaced the original pine nuts with crushed pecans. Pecans are more sustainable and, bonus, they’re cheaper.

Nasturtiums are whimsically scattered across the sunny half of my new garden. (Details on that — my new place — coming soon. Today we’re just making nasturtium pesto.) This plant has a way of doing that — whimsically scattering itself when it isn’t unrolling an entire carpet. Remember when we foraged nasturtium in that magical alley of Tropaeolum in the middle of the city?

It’s not at that level in my yard. But right now rich orange blooms are having a romp along the walkway to the back door, yellow, red-throated blooms are rising from the Edible Flower Box from our book, How to Window Box, and a coral flower bud has randomly appeared at the base of a potted Panache fig tree. All in a halestorm of flat round nasturtium leaves that go ga-doink when the wind hits them.

Nasturtium leaves piling up in the Edible Flower Box outside the back door.

A small tumble of nasturtium leaves and flowers under the kitchen window.

A nasturtium volunteer popping up next to our native Purisima Island mallow.

We’re already on record that we believe nasturtiums are underrated. For one, they’re easy to grow and interesting to look at, and the blooms and leaves are edible, with a peppery, watercress-like taste. Nasturtiums are not perennials — instead, nasturtiums are annuals that self-seed abundantly. If you grow a little patch of nasturtiums here, chances are you’ll see some plucky volunteers emerging over there, several feet away, in a matter of weeks. That isn’t everyone’s cup of tea, we know, so be advised.

Which reminds me, there’s even some nasturtium seedlings popping up by my native mallow.

Want to grow your own? We’ve been seeing four-inch pots of nasturtiums more and more at local nurseries. But as you might have inferred, you can readily grow nasturtium from seed. We’re growing some other produce from Baker Creek Seeds that have been coming in nicely, so good chance that their nasturtium seeds are worth a try.

Make sure to give your nasturtium (pronunciation: nas-TUR-shum) full sun outdoors, or part sun if you’re fine with minimal blooms. Water about once a week. Don’t fertilize it — nasturtium thrives on neglect and does better in somewhat poor soil. Snip spent blooms to spur more flowering.

Nasturtiums are aphid traps, so be sure to rinse your leaves and flowers thoroughly.

In our experience, nasturtium grows a lot easier than basil — in part because it isn’t as finicky about water and fertilizer. So nasturtium leaves make a great and always-on-hand, barely-have-to-think-about-it substitute when you’re making pesto. Adding in some flowers will give it some extra spiciness, but you don’t have to. I made the pesto in my mortar and pestle after a going down a rabbit hole about why mortar and pestles are superior to food processors when making pesto, and what material should it be — ceramic? Granite? Marble? Marble pestle with a wood mortar?

I got a marble on marble one, but am keeping my eye out for nice olivewood mortar. And I adapted Maurizio Valle’s prize-winning pesto recipe on Pasta Grannies’ YouTube channel to use nasturtium instead of basil. Note: the half teaspoon of salt in the video description is too much salt! And a whole garlic clove was too garlicky for my taste. The recipe below reflects the adjustments I made.

Before we dive in, make sure you give those nasturtium parts a strong rinse and exam because this plant can be an aphid trap. Great if you want to keep any nearby roses aphid-free, but not great on your plate.

Your homemade nasturtium pesto will comfortably coat two plates of pasta.

Serving size: 3 tablespoons (enough for two plates of pasta)

Time: 30 minutes

Equipment: marble mortar and pestle, or wood mortar and marble pestle

Ingredients:

• ~40 nasturtium leaves, stems removed, thoroughly rinsed with a little water clinging to the leaves, torn into pieces
• Optional: a few nasturtium flowers thrown in for extra spice
• Pinch (~1/4 teaspoon) rock salt
• 1/2 clove garlic thinly sliced (or more if you like it very garlicky)
• 3 tablespoons crushed pecans
• 4 tablespoons freshly grated parmesan
• 4 tablespoons extra virgin olive oil

Preparation:

Add garlic and salt to your pestle (the bowl part). Create a paste by grinding the mortar (the handheld part) against the pestle in a circular rocking movement.

Note: That’s the movement you’ll want throughout this process; try not to pound it. Regularly turn the pestle to get a better grip on your ingredients.

Add your nasturtium gradually, using your mortar to integrate the leaves (and flowers, if you’re using them) into the paste. Keep going until you have a uniform green puree in your pestle. Don’t worry, it transforms surprisingly fast!

Add crushed pecans gradually until combined, then parmesan gradually until combined.

Put down your mortar. Gently pour your olive oil in. Add more or less depending on your desired consistency. Use a spoon to mix.

Toss your pesto into your pasta, use in a grilled cheese sandwich, or dollop onto crackers.

—TH