1. Heat a small saucepan over low heat. Add oil to pan; swirl to coat. Add garlic; cook 5 minutes. Place beans and 1/3 cup water in a food processor. Add garlic mixture, ricotta cheese, and next 3 ingredients (through 1/4 teaspoon black pepper); process until smooth.
2. Place bean mixture in a 3-quart electric slow cooker. Cover and cook on LOW for 2 hours.
3. Stir in olives and lemon rind. Garnish with rosemary and pepper, if desired.