Catalonian Pepper and Nut Sauce (Salsa Romesco)
Romesco refers to the type of chile used to flavor this rich sauce. Romesco chiles can be difficult to find, so we use smoky ancho chiles. Much of the flavor in this sauce hinges on the sweet smoked paprika (pimentón de la Vera dulce); don't substitute regular paprika, which has duller flavor. This batch makes plenty for dressings, to stir into pasta, or to serve with eggs and toast. Freeze leftover sauce in ice-cube trays; transfer to zip-top plastic bags to freeze for up to one month. Thaw in the refrigerator; bring to room temperature to serve.