Preheat your oven to 350°F (175°C) and prepare three 9-inch round cake pans by greasing and lightly flouring them.

In a medium bowl, combine all-purpose flour, baking powder, baking soda, and salt. Whisk until well blended.

In a large mixing bowl, cream together unsalted butter and granulated sugar using an electric mixer on medium speed for about 3-5 minutes.

Add eggs one at a time, mixing well after each addition, then stir in vanilla extract.

Gradually add the dry flour mixture to the butter mixture, alternating it with buttermilk and cooled brewed coffee.

Pour the batter evenly into the prepared cake pans and smooth the tops.

Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean.

To make the caramel sauce, melt granulated sugar in a medium saucepan over medium heat, stirring constantly for about 5-7 minutes.

Once sugar is golden amber, add butter, stirring until melted. Slowly pour in heavy cream and stir until smooth.

In a large mixing bowl, beat unsalted butter until creamy. Gradually add powdered sugar, then add heavy cream, caramel sauce, vanilla extract, and cooled brewed coffee.

Frost the cooled cake layers by placing one layer on your serving platter and spreading buttercream on top. Repeat for the next layer.