Prepare Sweet Swirl™ Caramel Cake Mix as directed on package with 1 stick butter, water and rum – reserving Caramel packet. Meanwhile, melt remaining butter in a skillet over medium heat; add brown sugar, and cinnamon; bring to a simmer. Add bananas and simmer 1 additional minute; cool. Cut cooled cake into cubes; layer with bananas and whipped topping in a clear glass bowl. Drizzle with reserved Caramel topping, and chill until served. Makes 10 servings.