Davina uses this olive paste as a pizza topping, as a flavor pickup for purchased pasta sauces and as a spread for baguette slices.
Makes about 1 cup.
Heat oil in a heavy large skillet over low heat. Add onions, sauté until dark brown, occasionally scraping up brown bits, about 30 minutes Transfer onions to processor. Add tomatoes and olive. Using on/off turns, process until chunky paste forms (do not puree). Season with pepper. Cool. (Can be made one week ahead. Cover; chill. Bring to room temperature before using.)