Preheat your oven to 350°F (175°C) and prepare two round cake pans by greasing with butter and dusting with flour.

In a large mixing bowl, whisk together the all-purpose flour and baking powder until thoroughly combined.

Cream the softened unsalted butter with brown sugar and granulated sugar using an electric mixer until light and fluffy.

Add the eggs one at a time to the creamed mixture, mixing well after each addition until fully incorporated.

Gradually add the dry ingredient mixture to the wet mixture, alternating with the milk until just combined.

Pour the batter evenly into the prepared pans and bake for 25-30 minutes or until a toothpick comes out clean.

Prepare the salted caramel sauce by melting the granulated sugar and then adding the heavy cream and sea salt, stirring until smooth.

Once the cakes are cooled, layer them with salted caramel sauce in between and over the top, then sprinkle with sea salt.