Coffee Cake

1. Preheat your oven to 350F/ 180C and grease two 8-inch cake pans, set aside. 
2. In a large bowl whisk together the flour, baking powder, baking soda, and salt.
3. In a small bowl mix together the instant coffee and water.
4. In another large bowl with a handheld mixer or your stand mixer fitted with the paddle attachment beat the butter for 2 minutes, add the oil, and mix for an additional minute. 
5. Add the sugar and beat for 2-3 minutes, until light and fluffy. Add the eggs.
6. In a small cup or bowl add the coffee granulates and hot water- stir until the coffee granulates have disappeared. Add to the wet ingredients. 
7. Gently fold in half of the flour mixture, then half of the buttermilk then repeat with the remaining ingredients. Pour into prepared pans and bake for 20-25 minutes, or until you stick a toothpick in the center and only moist crumbs come out, no wet batter. Let cool on a wire rack for 20 minutes before inverting to cool completely. If you want you can prepare the frosting and whipped cream while the cakes are baking and store the frosting at cool room temperature and whipped cream in the fridge while you wait for the cakes to cool completely.

Coffe Frosting

1. In the bowl of an electric mixer fitted with a paddle attachment, or large bowl with a hand held mixer beat the butter for 5 full minutes, until light and fluffy. 
2. Sieve the powdered sugar to prevent any lumps and add half to butter. Beat for another 5 minutes then add the remaining powdered sugar and mix for 3 more minutes.
3. While powdered sugar is mixing into butter, in a small bowl add instant coffee and hot water. Add the coffee mixture to frosting with heavy cream and beat for another 3 minutes. Set aside while you make the whipped cream.

Coffee Whipped Cream

1. In a small bowl mix together the instant coffee and hot water and set aside. In a mixing bowl beat the heavy whipping cream, powdered sugar, dry milk powder (if using) and the coffee mixture. Beat until stiff peaks form.
2. On the serving plate place one layer of cake, if desired level off the top and cut any dome. Then spread with coffee buttercream on in an even layer and sprinkle 2 of the chopped Heath bars on top and place the second cake on top.
3. Spread the whipped cream on top of the cake and sprinkle the remaining chopped Heath bars. Store in the fridge for up to 5 days. Let the cake sit at room temperature for 30 minutes before eating for the best flavor.