Preheat the oven to 350ºF. Grease two 8-inch cake pans with shortening and dust with flour, tapping out excess.
In a medium bowl, whisk together milk, egg whites, almond extract, and vanilla extract until blended.
In the bowl of a stand mixer fitted with the paddle attachment, mix cake flour, sugar, baking powder, and salt on low speed. Cut the butter into cubes and add to the flour mixture, continuing to beat on low for 1-2 minutes.
Add all but ½ cup of the milk mixture and beat at medium speed for 1 ½ minutes. Add the remaining ½ cup of the milk mixture and beat for about 1 minute more. If necessary, scrape down the bowl and beater to remove any chunks and mix until the batter is a smooth consistency.
Pour the batter evenly between the two prepared cake pans. Bake until a toothpick inserted in the center comes out clean, 27-30 minutes. Allow the cake to cool to room temperature before removing from the pans. Once completely cooled, wrap the cake tightly in plastic wrap and place in the freezer. When you are ready to frost the cake, remove it from the freezer to thaw at room temperature while you prepare the frosting.
In a large bowl, cream butter and shortening with an electric mixer until fluffy. Add the confectioner's sugar two cups at at time until well incorporated. If the frosting gets too thick to be mixed you can add some of the heavy cream to thin it out. Add the salt, vanilla, and heavy cream and blend until combined, then blend on high until the frosting is light and fluffy. If you want a thinner frosting you can add more heavy cream (I recommend doing 2 teaspoons at a time), and if you prefer it sweeter you can add another cup of confectioner's sugar.
Divide frosting into separate bowls and tint to desired color with food coloring, mixing well. I left some white to use in the middle of the cake as well as a base for the rest of the decoration. Place one of your cold cakes onto the cake stand or platter you plan on using. Using an offset spatula, place a scoop of frosting in the center of the cake and spread it evenly across. Place the other cake carefully on top, making sure to line up the edges with the other cake. Place another dollop on top of this cake and spread a thin, even layer over the top and down onto the sides. Use this frosting to very thinly coat the entire cake, evening out any holes or edges and smoothing the sides.
I used Wiltons tip #233 and disposable pastry bags to pipe the colored frosting onto the cake. I held the tip to the cake and gave it a little burst to create the dots. It worked best with cold frosting. The warmer frosting made blobs while the cold frosting held its stippled shape really well. I stored the other colors of frosting in the refrigerator while I was working with another one and gave them a good stir before placing them in the piping bags.
Place the cake in the refrigerator until the frosting "crusts" a bit, then cover loosely with plastic wrap and store in the refrigerator until ready to serve.