Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition. Then, stir in the vanilla extract.
In a separate bowl, combine the flour, baking powder, baking soda, and salt. Gradually add this dry mixture to the wet ingredients, alternating with the buttermilk, starting and ending with the flour mixture. Mix until just combined.
Gently fold in the butterscotch sauce until evenly distributed throughout the batter.
Divide the batter evenly between the prepared cake pans. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
Allow the cakes to cool in the pans for 10 minutes, then transfer them to a wire rack to cool completely.
While the cakes are cooling, whip the heavy cream with the powdered sugar and vanilla extract until soft peaks form.
Once the cakes are completely cool, place one layer on a serving plate. Spread a layer of whipped cream on top, then place the second layer on top.
Frost the top and sides of the cake with the remaining whipped cream. Drizzle with caramel sauce if desired.