In a medium saucepan, combine granulated sugar and water. Bring to a simmer over medium heat and boil without stirring until it turns deep amber, about 10 minutes. Remove from heat and whisk in heavy cream and salted butter until smooth. Cool while preparing the cake.

Preheat oven to 350°F (175°C) and grease two 6-inch pans with flour. Whisk dry ingredients together in a bowl and mix wet ingredients in another. Combine wet and dry mixtures until just incorporated. Divide batter and bake for 25 minutes or until a toothpick comes out clean. Cool in pans for 10 minutes before transferring to a wire rack.

Beat softened salted butter in a mixing bowl until fluffy. Add espresso powder and vanilla extract, mixing well. Gradually add powdered sugar until creamy. Adjust texture with milk if too thick.

Slice cooled cakes in half horizontally to create four layers. Spread buttercream and drizzle caramel between layers. Repeat and finish with frosting on top and sides. Pour remaining caramel over the top.

Slice cake into portions and enjoy. Pairs well with vanilla ice cream or whipped cream.