01 - Preheat oven to 350°F. Grease and line three 8-inch round cake pans with parchment paper.
02 - In a medium bowl, whisk together the all-purpose flour, baking powder, and salt until evenly distributed.
03 - In a large bowl, beat the softened butter and granulated sugar using an electric mixer on medium speed until pale, light, and fluffy, approximately 3 to 4 minutes.
04 - Add the eggs one at a time, mixing thoroughly after each addition. Stir in the vanilla extract until fully blended.
05 - Add the flour mixture in three additions, alternating with the whole milk in two additions, beginning and ending with the flour. Mix until just combined; avoid overmixing.
06 - Divide the batter evenly among the three prepared cake pans. Smooth the tops with an offset spatula for even layers.
07 - Bake for 25 to 30 minutes, or until a toothpick inserted into the center comes out clean. Allow the cakes to cool in the pans for 10 minutes, then invert onto wire racks to cool completely.
08 - Beat the softened butter with an electric mixer until creamy. Gradually add the sifted powdered sugar on low speed. Pour in the heavy cream, vanilla extract, and salt, then beat on high speed until light and fluffy, about 3 minutes.
09 - Level the cooled cake layers with a serrated knife if domed. Place the first layer on a cake stand and spread an even layer of buttercream over the top. Repeat with the remaining layers.
10 - Apply a smooth, even coat of buttercream over the top and sides of the assembled cake using an offset spatula.
11 - Arrange fondant graduation caps, diploma shapes, and edible gold pearls as desired. Personalize with the graduate's name or class year using fondant lettering.