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 mixing bowl, beat the softened butter and granulated sugar using an electric mixer on medium-high 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 to avoid overworking the batter.
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. Let the cakes cool in the pans for 10 minutes, then invert onto wire racks to cool completely.
08 - Beat the softened butter in a mixing bowl until smooth and creamy. Gradually add the sifted powdered sugar on low speed. Pour in the heavy cream, vanilla extract, and salt, then increase to high speed and beat until light and fluffy, approximately 3 minutes.
09 - Level the cooled cake layers with a serrated knife if necessary. Place the first layer on a cake stand and spread an even layer of buttercream over the top. Repeat with the remaining layers, stacking neatly.
10 - Apply a smooth, even coat of buttercream over the top and sides of the assembled cake using an offset spatula, creating a clean finish.
11 - Decorate with shaped fondant graduation caps, diplomas, and edible gold pearls as desired. Personalize with the graduate's name or class year for a celebratory finish.