Preheat the oven to 350 degrees F (180 degrees C).
Grease a 9x9 baking pan and set aside.
In an electric mixer with the paddle attachment, beat the Butter (1 stick), Granulated Sugar (3/4 cup), and Brown Sugar (3/4 cup) until light and fluffy.
Add the Light Sour Cream (1/2 cup), Banana (3), Egg (2), and Vanilla Extract (2 teaspoon). Mix until combined.
Add the All-Purpose Flour (2 1/4 cup), Baking Powder (3/4 teaspoon), Baking Soda (1 1/2 teaspoon), and Salt (1/2 teaspoon). Mix until combined.
Prepare the crumble by mixing the crushed Heath Bar (1 1/2 cup), Brown Sugar (2 tablespoon) and Ground Cinnamon (1 tablespoon). Add half to the batter, mix, and pour into the prepared baking pan.
Sprinkle the remaining crumble on top and bake for 50 minutes to 1 hour, or until a cake tester comes out clean.
Allow to cool and drizzle with Caramel Sauce (to taste).