Preheat your oven to 350 degrees F (175 degrees C). Grease and flour a 9×9-inch baking pan or line it with parchment paper.

In a medium bowl, whisk together flour, granulated sugar, baking powder, baking soda, and salt.

In another bowl, beat the softened butter and egg together until light and fluffy.

Stir in brewed coffee, buttermilk, and vanilla extract until combined.

Gradually fold in the dry ingredients until smooth. Pour the batter into the prepared pan.

Bake for 25-30 minutes, or until a toothpick inserted comes out clean. Let cool in the pan for 10 minutes before transferring to a wire rack to cool completely.

In a saucepan, mix together brown sugar, butter, and heavy cream, stirring gently until it simmers and thickens.

Remove from heat and stir in vanilla extract and a pinch of salt.

Mix brewed coffee and powdered sugar until smooth.

Once the cake is cool, poke holes in the top and pour warm caramel sauce over the cake.

Drizzle with the coffee mixture before serving.