If you make these, you'll want to leave yourself plenty of time for freezing, crumb-coating, chilling, and decorating. Start at least 2 days in advance.
Baby Block Mini-Cakes
(makes about 15)
1. Make a 1 and 1/2 quantity (requires a little math!) of my favorite buttermilk cake batter (I added the zest of one lemon) and divide the batter evenly among two parchment-lined rimmed half-sheet pans (like the one in the photo). Bake at 325 degrees F convection (350 non-convection) for 16 minutes, or until done when tested with a toothpick. Cool completely, remove from the pan and transfer the cake to another plastic wrap-lined half sheet pan. Wrap in plastic wrap and freeze until firm.
2. Cut out the animal shapes from marshmallow fondant and keep them in an airtight container until ready to use.
3. Once the cakes are frozen, make the vanilla swiss meringue buttercream (recipe follows). Unwrap one cake layer and place in a plastic wrap-lined sheet pan, apply the desired amount of icing, then place the other cake layer on top. Chill until icing is firm. Cut the edges from the cake (where the cake is not level) and then cut the cake into squares approximately 3 inches on all sides. Apply a thin layer of icing to all sides of the block except the bottom (this is called the crumb coat). I held each block on the top and bottom and coated the sides first, then set the block down and applied icing to the top. A small offset spatula works well for this. Chill or freeze again until icing is firm.
3. Apply a second coat of icing to the blocks, place the fondant shapes onto the blocks where you want them. It helps if you place a fondant shape on at least two opposing sides of the block, because you can then pickup the blocks, touching where the fondant is, and it will be easier to work on them without messing up the icing. Carefully place the blocks onto slightly flattened cupcake papers or other liners. Chill again until firm.
5. Pipe the border and letters/numbers on the remaining sides using a #2 or 3 piping tip. Chill until set. Allow the cakes to come to room temperature before serving.
Vanilla Swiss Meringue Buttercream
9 ounces egg whites
15 3/4 ounces granulated sugar
1/2 teaspoon salt
24 ounces (6 sticks) unsalted butter, at cool room temperature, cut into tablespoon-sized pieces
2 teaspoons vanilla
Place 2 inches of water in a medium saucepan and bring the water to a simmer. Choose a saucepan that your mixer bowl will fit on top of without touching the water. In your mixer bowl, place the egg whites, sugar, and salt and whisk to combine. Place the bowl over the simmering water and continue to whisk until the sugar is fully dissolved and the mixture is very hot to the touch, about 130-140 degrees F.
Remove the bowl from the double boiler and place on your stand mixer fitted with a whisk attachment. Whisk at medium-high speed until the outside of the mixer bowl is room temperature. It is very important that the meringue be completely cool before adding the butter.
Add the butter, a tablespoon at a time, letting each tablespoon disappear before adding the next. After all the butter has been added, switch to the paddle attachment and beat until the mixture becomes fluffy and thick. This could take up to an additional 5 minutes or so. The mixture will go through a stage where it looks curdled before it reaches the proper consistency.
Add the vanilla and beat until completely combined, about a minute.