1. Put the beans in the bowl of a food processor with 1 garlic clove and a healthy pinch of salt. Turn the machine on and add the 1/4 cup olive oil in a steady stream through the feed tube; process until the mixture is smooth. Taste; add more garlic if you like, then puree again.
2. Place mixture in a bowl and use a wooden spoon to beat in rosemary, lemon zest, and remaining 1 tablespoon olive oil. Taste and add salt and pepper as needed. Use immediately or refrigerate a day or two. Serve with pita triangles or crudite. Makes about 1-2/3 cups.