Spray inside of 6-quart slow cooker with no stick cooking spray. For the Cake, mix all ingredients in large bowl. Pour into greased slow cooker. Place clean, dry hand towel over slow cooker and cover with lid.
Cook 3 1/2 hours on LOW or until cake is almost set.
Meanwhile, for the Caramel Sauce, cook and stir all ingredients in small saucepan on medium-high heat 5 minutes or until sauce is smooth.
Carefully remove slow cooker insert and place on wire rack. Pour 1/2 of the Caramel Sauce over the cake. Let stand 10 to 15 minutes to cool slightly. Serve cake with remaining sauce, and ice cream or whipped cream, if desired.