2 tablespoons unsalted butter, melted
6 slices challah bread, each 1-1/4 inches thick, cut into 1/2-inch cubes
1/2 cup golden raisins
1 cup milk
1 container (15 ounces) ricotta cheese
1/2 cup sugar
1 cup sour cream
1 teaspoon grated lemon zest
1 teaspoon vanilla extract
1/4 teaspoon ground cinnamon
1. Coat a 1-1/2-quart souffle dish with 1 tablespoon melted butter. Add bread and raisins to dish. Pour milk over top; stir to combine. Set aside.
2. Mix together the ricotta, sugar, eggs, sour cream, lemon zest and vanilla. Pour ricotta mixture over bread; mix lightly. Drizzle remaining 1 tablespoon butter over bread and sprinkle with cinnamon. Cover dish with aluminum foil; place in slow cooker bowl. Fill bowl with boiling water to reach 1 inch up the side of dish.
3. Cover top of slow cooker with a dish towel; top with lid. Cook for 2-1/2 hours on HIGH or until internal temperature registers 140° on an instant-read thermometer. Cool at least 20 minutes.