Preheat oven to 350 degrees F (180 degrees C). Line three 8-inch, and three 6-inch round pans with parchment rounds, and grease with
Non-Stick Baking Spray (as needed)
All-Purpose Flour (4 3/4 cups)
Baking Powder (1 Tbsp)
Granulated Sugar (4 1/2 cups)
Salt (1/2 Tbsp)
in a stand mixer with a paddle attachment until fully combined.
Mix chunks of
Unsalted Butter (1 1/2 cups)
slowly into the dry mix, at a low speed. Continue to mix until no large chunks of butter remain, and the mixture becomes crumbly.
Pasteurized Egg Whites (1 1/2 cups)
, and mix on low until just incorporated. Mix in the
Buttermilk (2 1/4 cups)
in two installments, at a low speed.
Vanilla Extract (1 Tbsp)
Vegetable Oil (2 Tbsp)
, and mix at a low speed until fully incorporated. Scrape down the sides of the bowl with a spatula, then beat on low speed for about 15 seconds (the key is to mix until the ingredients are just incorporated so that the batter isn't overmixed).
Divide the batter into three different bowls. Add a different color of
Food Coloring (to taste)
into each bowl. Mix the color in by hand using a rubber spatula, scraping the sides and bottom of the bowl partway through. Mix until the batter is evenly colored.
Divide batter evenly between the prepared cake pans using a spoon. Fill each pan about 1-inch high with batter, then swirl the colors together using a butter knife or small offset spatula.
Bake for 32-35 minutes, or until a toothpick comes out clean. Allow the pans to cool for 10 minutes, then run an offset spatula around the perimeter of the pan to separate the cake from the pan. Once the layers are fully cooled, use a serrated knife to create a flatter surface on the cake tops.
While the cake layers bake and cool, make the Vanilla Buttercream Frosting. Beat the
Unsalted Butter (4 cups)
on medium speed for 30 seconds with a paddle attachment, until smooth.
Slowly add in the
Powdered Confectioners Sugar (16 cups)
, 1 cup at a time. Alternate with small splashes of
Heavy Cream (1/2 cup)
Once fully mixed, add in the
Vanilla Extract (2 Tbsp)
Salt (1/2 Tbsp)
, and beat on low until the ingredients are fully incorporated, and the desired consistency is reached. If the frosting is too thick, add in additional cream (1 tsp at a time). If the frosting is too thin, add in more powdered sugar (a quarter cup at a time).
To assemble, cut a hole in the center of the greaseproof cake board using a knife. Use a dab of frosting to help stick the first cake layer to the board.
Add an even layer of buttercream between the cake layers. Flip the top layer over before placing it on the stack so the flatter side faces up.
Apply a thin coat of frosting around the cake, to fully cover the cake layers. Smooth using a bench scraper, then chill the cake in the fridge (20 minutes) or freezer (5 minutes) until the frosting is firm to the touch.
Trim 4 bubble tea straws to be the exact height of the tier, and insert them an even distance apart, about 2 ½-inches from the center of the cake to help support the top tier. Before inserting the center dowel use a straw to remove some cake to allow the dowel to line up with the hole you cut in the cakeboard. Place a central wooden dowel into the center of the 8-inch cake. Chill the cakes again in the fridge (20 minutes) or freezer (5 minutes) until the frosting is firm to the touch.
While the 8-inch tier chills, frost the 6-inch tier. Cut a hole in the center of the greaseproof cake board using a knife. Use a dab of frosting to help stick the first cake layer to the board, just as you did before. Add an even layer of buttercream between the cake layers. Apply a thin coat of frosting around the cake, to fully cover the cake layers. Smooth using a bench scraper, then chill the cake in the fridge (20 minutes) or freezer (5 minutes) until the frosting is firm to the touch.
Then place the tier on top with the dowel in the middle until it rests on the 8-inch tier.
Fresh Fruits (to taste)
Fresh Mixed Berries (to taste)
Pipe more buttercream around the base of the top tier and around the top of the cake. Press the fruit into the frosting to decorate.
To keep the berries fresh, brush on a glaze of honey.