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 until well blended.
03 - Beat butter and sugar in a large mixing bowl until light and fluffy, approximately 3-4 minutes. Add eggs one at a time, incorporating fully before each addition. Mix in vanilla extract.
04 - Alternate adding flour mixture and milk to creamed mixture in three additions, beginning and ending with flour. Mix until just incorporated, being careful not to overmix.
05 - Divide batter evenly among prepared pans. Bake for 28-32 minutes until a toothpick inserted in center comes out clean. Cool in pans for 10 minutes, then release onto wire racks to cool completely.
06 - Combine sugar and water in a heavy saucepan over medium heat. Swirl pan gently until sugar dissolves. Increase heat to medium-high and cook until mixture reaches golden amber color, approximately 7-10 minutes. Remove from heat and carefully whisk in butter, followed by cream and salt. Cool to room temperature.
07 - Beat butter until creamy. Gradually incorporate powdered sugar, then add caramel sauce, vanilla, and salt. Continue beating until light and fluffy, about 2-3 minutes.
08 - Place first cake layer on serving platter and spread with generous layer of caramel frosting. Repeat with remaining layers. Apply frosting to top and sides of assembled cake. Drizzle with reserved caramel sauce for glossy finish. Refrigerate for at least 30 minutes before serving to ensure clean slices.