Creating this Salted Caramel Cake is straightforward if you follow these detailed steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease and flour three 8-inch round cake pans.
2. Mix Dry Ingredients: In a large bowl, sift together the flour, baking powder, and salt. Set aside.
3. Cream Butter and Sugar: In another bowl, beat the softened butter and granulated sugar together until light and fluffy.
4. Add Eggs: Add the eggs one at a time, mixing well after each addition. Then add the vanilla extract.
5. Combine Mixtures: Gradually add the dry ingredients to the butter mixture, alternating with the milk. Mix until just combined and smooth.
6. Divide Batter: Evenly divide the batter among the prepared cake pans.
7. Bake: Place in the preheated oven and bake for 35-40 minutes, or until a toothpick inserted in the center comes out clean.
8. Cool the Cakes: Remove from the oven and allow the cakes to cool in the pans for 10 minutes. Transfer to wire racks to cool completely.
9. Make Salted Caramel Sauce: In a saucepan, heat the sugar over medium heat. Stir continuously until it melts and turns a golden brown.
10. Add Butter and Cream: Once melted, carefully add the butter and stir until melted. Gradually add the heavy cream and stir until smooth. Remove from heat and mix in sea salt.
11. Prepare the Frosting: In a mixing bowl, beat the softened butter until creamy. Gradually add the powdered sugar and mix until smooth. Add the salted caramel sauce and mix until well combined.
12. Assemble the Cake: Place one cake layer on a serving plate. Spread a layer of frosting on top, then drizzle with salted caramel sauce. Repeat with the second layer.
13. Top the Cake: Place the third layer on top and frost the entire cake with the remaining frosting. Drizzle more salted caramel on top for decoration.
14. Chill: Place the assembled cake in the refrigerator for about 30 minutes to set the frosting.

With these steps, you will have a stunning Salted Caramel Cake ready to impress anyone who tastes it!