STEP ONEHEAT oven to 350º F. Coat 9x5x3-inch loaf pan with no-stick cooking spray. Stir together muffin mix, 1 egg, sour cream and 3/4 cup milk in large bowl just until blended. Pour into prepared pan. Bake 50 to 55 minutes or until toothpick inserted in center comes out clean. Cool pan 10 minutes. Turn out onto cooling rack. Cool completely. Cut into approximately 3/4-inch cubes.
STEP TWOREDUCE heat to 325º F. Coat 9x9-inch baking pan with no-stick cooking spray. Place banana bread cubes in pan. Microwave white baking chips in uncovered microwave-safe bowl on MEDIUM HIGH power for 1 minute and 15 seconds. Stir. If neccessary, microwave in 15 second increments, stirring just until melted. Combine 2 cups milk and cream in medium saucepan. Bring to a boil over medium heat. Combine 3 eggs, egg yolks and sugar in large bowl. Gradually whisk in milk mixture. Add melted chocolate. Whisk until blended.
STEP THREEPOUR egg mixture over bread cubes pressing down slightly to submerge. Let stand 15 minutes. Cover pan with foil. Bake 60 to 65 minutes or until pudding is firm and a knife inserted in center comes out clean. Serve warm or at room temperature. Warm caramel topping according to package directions. Drizzle over pudding.