Romesco sauce, from the Catalonian region of Spain, is traditionally served with shellfish. We serve our version with roasted potatoes. It's even better the next day, when the flavors have had a chance to blend: Refrigerate sauce overnight in a covered container, and bring to room temperature before serving.
Martha Stewart Living, October 2003, Annual Recipes 2004, MSL Cookbook Vol. 2; The New Classics, Martha Stewart Living, October 2003