Roasted Asparagus & Green Onions with Romesco

In Spain, the seasonal arrival of a certain chile pepper or mushroom is often marked with a food festival. The calçot is a type of green onion that grows in the northern Spanish region of Catalonia. It’s served grilled with romesco—a kind of pesto made with roasted bell peppers and almonds—at an annual festival called Calçotada. Here, use the freshest green onions for your at-home fiesta.