Prepare the Caramel:
Heat brown sugar, butter, and heavy cream in a saucepan until smooth. Pour into the cake pan.
Preheat the Oven:
Set to 350°F (175°C). Let the caramel sit while you prepare the batter.
Make the Cake Batter:
Beat butter and sugar until fluffy. Add eggs, vanilla, and coffee. Mix well.
Combine Dry Ingredients:
Whisk flour, baking powder, and salt. Slowly fold into the wet mixture.
Assemble the Cake:
Pour batter over the caramel layer. Smooth the top with a spatula.
Bake:
Place in the oven for 40 minutes. A toothpick should come out clean.
Flip Carefully:
Let it rest for 10 minutes. Then, turn it onto a plate.
Serve Warm:
Enjoy with a strong coffee or a scoop of ice cream.