Prepare 3 9-inch cake pans with shortening and flour.
Combine flour, baking powder, baking soda, and salt with a whisk in a large bowl. Set aside.
Cream butter until fluffy and then add sugar. Cream together for about 8 more minutes.
Add eggs, 1 at a time, and cream together after each.
Add flour mixture and buttermilk, alternately, beginning and ending with flour. Combine each addition of flour and then turn mixer on high to add air into the batter.
Add vanilla and beat well. Turn mixer on high once vanilla has been incorporated for about 10 seconds to lighten batter.
Divide among pans and bake for 25-30 minutes until set.
Turn out of pans onto cooling racks and allow to cool completely.
Salted Caramel Buttercream Recipe
Add all ingredients from the first stage of the frosting recipe in a 3-4 quart pot. Stir ingredients with a wooden spoon as cooking over medium-low heat.
Cook to softball stage (235-245 degrees on a candy thermometer as well as using the cold water test).
Remove from heat and pour into a large mixing bowl or the bowl of a stand mixer. Using a whip attachment, whip the caramel until it has cooled enough to touch lightly.
Add the butter and salt from the second stage of the frosting recipe to the mixing bowl and whip.
Add confectioner's sugar in 1/2 cup increments, stopping after each to scrape sides of mixing bowl. Turn mixer onto high for about 10 seconds after each addition to incorporate air into the frosting.
Adjust the amount of confectioner's sugar to result in a frosting that will hold shape.
Frost cake and store on a cake plate covered with a dome or an airtight container.
Best served within 1-3 days.
For easier frosting of cake, wrap tightly in parchment and aluminum foil and freeze overnight. Brush the cake with a pastry brush to remove loose crumbs and then frost the cake with a light layer of frosting to create a crumb coating. Then, frost the cake as normal.
Butter Cake with Salted Caramel Buttercream Frosting Recipe https://addapinch.com/salted-caramel-buttercream-frosting-recipe/