Preheat your oven to 325°F (163°C) and line two 8-inch round pans with parchment paper.

In a stand mixer, sift together 2 cups of cake flour, 1 ½ cups of granulated sugar, baking powder, baking soda, and salt on low speed.

Add room-temperature butter, cut into chunks, and beat on medium speed until it resembles wet sand.

Slowly mix in 1 cup of buttermilk and a splash of vanilla extract, beating for about 2 minutes until smooth.

Add the eggs one at a time, beating well after each addition for about 5 minutes until creamy and fluffy.

Divide the batter evenly between the prepared pans and tap them gently against the counter.

Bake for 30-35 minutes, or until golden and spring back when pressed gently.

While cakes cool, melt 1 stick of unsalted butter, whisk in 2 cups of dark brown sugar, and let it bubble until smooth.

Stir in ⅔ cup of heavy cream and cook for about 2 minutes until thick and smooth.

Gradually add 2 cups of powdered sugar and salt, then incorporate the remaining butter until creamy.

Once cakes are cooled, layer and frost the top with salted caramel frosting.

Frost the sides of the cake gently and sprinkle flaky sea salt on top.

Let the cake sit for at least 15 minutes before serving.