Cook 1 pound frozen peas with 4 tablespoons each butter and water and 1/2 teaspoon salt in a saucepan over medium heat until soft, 12 to 15 minutes. Uncover and smash with a potato masher to make a chunky puree. Stir in 1/2 teaspoon each lemon zest and pepper. Season with salt and thin with 2 to 3 tablespoons water.
Photograph by Ryan Dausch