Preheat your oven to 350°F (175°C). Grease and flour a cake pan.
In a mixing bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.
Add the softened butter and mix until the mixture resembles coarse crumbs.
In another bowl, whisk together the eggs, vanilla extract, milk, and coffee.
Gradually add the wet ingredients to the dry ingredients, mixing until just combined.
Pour the batter into the prepared cake pan and bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
For the frosting, beat the softened butter until creamy. Gradually add the powdered sugar, heavy cream, and vanilla extract, beating until smooth and fluffy.
Frost the cooled cake with the buttercream frosting and drizzle with caramel sauce.