This unique layer cake is definitely worthy of its own celebration. It may look complicated, but we'll teach you step-by-step how to make this gorgeous layer cake recipe!
Make this cake in stages. Prepare and cool the cakes, frost and chill the layers, then assemble and decorate. Make three batches of cake batter to have enough for all the layers shown. Any leftover batter can be used to make cupcakes.
Allow egg whites and butter to stand at room temperature for 30 minutes. For cakes, use one 8x8x2-inch square baking pan, two 8x1-1/2-inch round baking pans, one 9x5x3-inch loaf pan, and two 3-cup oven-safe glass bowls. Grease bottoms of pans and bowls. Line bottoms of pans and bowls with parchment paper; grease and lightly flour bottoms and sides of pans and bowls. Set pans and bowls aside.
In a medium bowl stir together flour, baking powder, baking soda, and salt; set aside. Preheat oven to 350°F. In a large mixing bowl beat butter with electric mixer on medium to high for 30 seconds. Add sugar and the seeds scraped from the vanilla bean half or the vanilla. Beat until well combined, scraping sides of bowl occasionally. Add egg whites, one at a time, beating well after each addition. Alternately add flour mixture and buttermilk to butter mixture, beating on low after each addition just until combined.
Bake cakes in batches to ensure even baking and avoid crowding oven. Cover and refrigerate batter until ready to fill pans. Divide batter among pans as bowls as follows: 4 cups batter in 8-inch square pan (bake about 50 minutes); 2-1/2 cups batter in each 8-inch round pan (bake 40 to 45 minutes); 2-1/2 cups batter in 9-inch loaf pan (bake 35 to 40 minutes); and 1 cup batter in each 3-cup bowl (bake at 325°F for 45 to 50 minutes).** Bake until a wooden toothpick inserted near center of each cake comes out clean. (Avoid checking cakes too early, which may cause them to fall.)
Cool cakes in pans or bowls on wire racks for 10 minutes. Remove from pans or bowls. Cool completely.
Prepare three recipes of Almost-Homemade Vanilla Buttercream. Place the square layer, the base cake, on a serving platter. Spread frosting on top and sides and make smooth. Insert five to six straws in center of square, flush with top, to help support layers that follow. Chill at least 30 minutes to dry frosting.
Cut one piece of clean cardboard slightly smaller than round layers. Add a dab of frosting to the center of the cardboard. Place one 8-inch round cake on cardboard; place, cardboard-side down, on a flat plate. Spread top with frosting. Stack second 8-inch round on frosted layer; do not frost. Chill 30 minutes for easier cutting. With a long serrated knife, horizontally slice top layer at an angle, cutting from top edge to bottom edge. Set aside sliced top. Thinly spread frosting on stacked sliced layer, then replace removed layer, positioning wide edge on higher side to form a slant. Spread top and sides with frosting to make smooth. Insert straws into center of layers to secure; cut flush with top. Chill at least 30 minutes to dry frosting. Meanwhile, cut loaf cake in half crosswise. Cut a clean piece of cardboard slightly smaller than one loaf cake half; add a dab of frosting to the center and set aside. Spread top of one cake loaf with frosting. Layer second loaf cake half on frosted layer; do not frost. Chill 30 minutes for easier cutting. With a long serrated knife, horizontally slice top cake layer at an angle, cutting from top edge to bottom edge. Set aside sliced top. Thinly spread frosting on stacked sliced layer, then replace removed layer, positioning wide edge on higher side to form a slant. Trim tall side flat, if necessary. Invert stack and place on cardboard piece; place, cardboard-side down, on a flat plate. Spread top and sides with frosting (tinted, if desired) to make smooth. Insert straws into center of layers to secure; cut flush with top. Chill at least 30 minutes to dry frosting. Cut a 2 1/4-inch round clean cardboard piece; add a dab of frosting to the center and set aside. Spread frosting on flat side of one bowl-shape cake. To form a ball, place flat sides of both bowl-shape cakes together. Place one rounded side of the ball on the cardboard. Place, cardboard-side down, on a small plate. Insert a straw through halves (do not trim). Spread frosting on ball to make smooth, then chill at least 30 minutes to dry frosting (leave straw in cake).
Loosen slanted round layers from plate and using a wide spatula, carefully transfer slanted round layers (cardboard intact) to top of square layer (you can also insert another straw through the cake layers to use as a handle on top; trim flush with top of cake or remove when done). Loosen loaf cake layers from plate and place on slanted round (cardboard intact), slanted sides together. Using a wide spatula and the straw as a handle, place ball on top of stacked cakes***; cut straw flush with top. Touch up with frosting.
Pipe decorative designs of tinted frosting, using a pastry bag fitted with a small round tip, from bottom layer to top. On bottom layer, pipe small dots and large concentric circles. Center sugar pearls in some small dots. On slanted round layer, mark vertical lines with a skewer, then fill in lines with frosting. On next layer, pipe flower centers. Then pipe petals by pulling ends away from centers. Place sugar pearls on centers. On top ball, randomly pipe dots. Place sugar pearls between dots. For bow, tint candy clay. Roll out to 1/8-inch thickness and cut an 11x1 1/4-inch strip. Fold short ends of strip together in center, overlapping slightly. Pinch center. Cut a 3x3/4-inch strip from rolled clay and wrap around center; press lightly to secure, trimming if necessary. Insert a wooden toothpick in bottom center of bow. Position bow on cake, inserting slightly off-center.
To make sour milk, place 4 tsp. lemon juice or vinegar in a 2-cup glass measuring cup. Add enough milk to equal 1 cup total liquid; stir. Let stand 5 minutes before using.
Use any leftover batter to make cupcakes.
For extra stability, remove the ball cake from the cardboard piece and place on top of stacked layers. Press the straw in the ball cake all the way down into the layers underneath.
In medium-size microwave-safe bowl, melt candy at 100% power (high) for about 1 minute total, stopping to stir every 20 seconds, until melted and smooth. Do not overheat pieces.
Stir in corn syrup with a rubber spatula until well-combined; mixture will look grainy. Tightly cover clay with plastic wrap. Let stand at room temperature at least 1 hour to firm. (Let semisweet chocolate clay stand at least 2 hours to firm.)
To roll firm clay, lightly dust a clean work surface with powdered sugar. Knead the clay until smooth. (To soften candy clay that was made several days ahead and has become firm, warm in a microwave for 5 to 10 seconds.)
Tint white candy clay with food coloring, kneading clay thoroughly to distribute color. Divide candy clay in small portions. To form shapes, work candy clay to resemble characters or designs. To roll clay, roll portions between sheets of waxed paper to 1/8-inch or less thickness. Cut shapes with cookie cutters, a small knife, or clean scissors. To keep clay pliable (or shapes from drying) while working with it, place clay and/or shapes on a baking sheet lined with waxed paper. Cover with plastic wrap.
Use this delicious, easy-to-shape white chocolate candy clay as you would fondant.
In large mixing bowl beat softened butter with mixer on medium until light and fluffy. Add marshmallow creme; beat until smooth, scraping sides of bowl. Add powdered sugar and vanilla; beat until light and fluffy. If frosting is too stiff to spread, soften in microwave oven no more than 10 seconds, then beat again until smooth.
Frost cake immediately. Or, to store, cover and refrigerate up to 3 days or freeze up to 1 month. Bring to room temperature before frosting cake. Makes 3 cups.
If only 13-oz. jars of marshmallow creme are available, purchase additional, then add 3 oz. (3/4 cup).