Romesco Sauce

This Catalan classic comes from the city of Tarragona, the old Roman capital (of what’s now Spain) about 60 kilometers south of Barcelona. For the sauce to be perfectly authentic, it must contain a chile almost never seen in the United States, a medium-hot little pepper called the nora. (Mulattos make a good substitute.) Here is a version I adapted from Colman Andrews’s authoritative book Catalan Cuisine.