01 - Preheat oven to 350°F. Grease and flour three 8-inch cake pans and line bottoms with parchment paper.
02 - Whisk together flour, baking powder, and salt in a medium bowl.
03 - Beat butter and sugar in a large mixing bowl until light and fluffy, approximately 3-4 minutes. Add eggs one at a time, then incorporate vanilla extract.
04 - Alternate adding flour mixture and milk to creamed batter in three additions, beginning and ending with flour. Mix until just incorporated.
05 - Divide batter evenly among prepared pans. Bake for 28-32 minutes until a toothpick inserted in the center exits clean. Cool for 10 minutes in pans, then transfer to wire racks to cool completely.
06 - Combine sugar and water in a heavy saucepan over medium heat, swirling until sugar dissolves. Increase to medium-high heat and cook until golden amber, 7-10 minutes. Remove from heat and whisk in butter, cream, and salt. Cool to room temperature.
07 - Beat butter until creamy. Gradually incorporate powdered sugar, followed by caramel sauce, vanilla, and salt. Beat until light and fluffy for 2-3 minutes.
08 - Place one cake layer on a serving platter and spread with a generous layer of frosting. Repeat with remaining layers. Frost top and sides, then drizzle additional caramel sauce over the top.
09 - Refrigerate for at least 30 minutes before serving to ensure clean slices.