Add the peas, garlic, seeds, lemon zest, lemon juice, salt, and pepper to a small food processor or blending container (if using an immersion blender).
200 grams (1 ⅓ cups) little green peas, 1-2 cloves garlic, 50 grams (¼ cup) seeds or nuts, Zest 1 lemon, Juice 1 lemon, ½ teaspoon sea salt, ½ teaspoon black pepper
Blend until combined. The mixture won't be smooth but the peas should be pretty broken down and the seeds roughly chopped.
Add the olive oil in a slow stream while blending. Season to taste and serve as you'd like. If you want a thinner pesto, add a splash of water while blending (make sure to adjust the seasoning). This can be refrigerated for a couple of days but is best served immediately.
3 tablespoons olive oil
Notes
If you're using frozen peas, quickly thaw them by covering with boiling water (from a kettle) for a minute, then draining.