Preheat your oven to 350°F (175°C) and grease two 9-inch round cake pans. In a large bowl, whisk together the flour, cocoa powder, baking soda, baking powder, and salt.

In a separate bowl, combine the sugar, eggs, buttermilk, and vegetable oil until well mixed.

Gradually stir the dry ingredients into the wet mixture, alternating with hot water, until just combined to create a smooth batter.

Divide the batter evenly between the prepared pans. Bake for 30-35 minutes until a toothpick inserted comes out clean.

Allow the cakes to cool in the pans for about 10 minutes before transferring to wire racks to cool completely.

For the frosting, beat softened unsalted butter until creamy. Gradually mix in caramel sauce until fluffy.

Once the cake layers are completely cooled, place one on a serving plate, spread with frosting, and sprinkle with toffee bits.

Add the second layer, frosting the top and sides for a smooth finish.

Drizzle additional caramel sauce over the frosted cake and add more toffee bits if desired. Slice and serve.