Preheat oven to 350°F (175°C).
Prepare three 8-inch cake pans with parchment paper, butter, and flour.
Whisk dry ingredients (flour, baking powder, baking soda, salt) in a bowl.
Cream butter and sugar until fluffy (3-4 minutes).
Add eggs one at a time, then vanilla extract.
Alternate adding dry ingredients and buttermilk, beginning and ending with dry.
Divide batter between pans and bake 25-30 minutes.
Make caramel by melting sugar until amber colored, then adding butter and cream.
Add sea salt to caramel and cool completely.
Make frosting by beating butter, gradually adding sugar, then caramel and salt.
Assemble cake by layering cake, frosting, and caramel drizzle.
Frost exterior and decorate with caramel drips and sea salt flakes.