Kombu, a green kelp that's sold in dried, leathery sheets, is a basic building block of Japanese dashi. We've been using it to make a full-bodied vegetarian stock but hated the idea of throwing it out post-simmer. That got us thinking: Why not use it in a pesto?
Soaked or cooked kombu blends easily into a silky sauce and plays well with any combination of pesto-friendly aromatics (citrus zests, garlic, chiles), herbs, and nuts. The slightly briny pesto is perfectly suited to light seafood dishes and is more likely than herb pestos to keep its bright green hue when hit with the heat from grilled meats or steaming bowls of pasta.
Kombu pesto will keep in the fridge for days, which is good news as you'll find plenty of uses for it: salads, vegetable hashes, slathered on burgers, or tossed with roasted or steamed vegetables. Add a heap of pesto-dredged greens to kombu broth for a soupe au pistouof the sea.