Vanilla Funfetti Cake

1. Preheat oven to 350ºF. Butter three 8"-9" round cake pans*, line bottoms with parchment rounds, and dust with flour, tapping out excess.
2. Sift the flour, baking powder, and salt into a bowl and whisk together.
3. In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter and sugar on medium-high speed until light, fluffy, and smooth. Reduce the speed to medium and add the egg whites gradually, beating each addition in until well-incorporated into the mixture. Wipe down the bowl and beater as needed.
4. Separately, whisk together the buttermilk, vanilla extract, and almond extract.
5. With the mixer on lowest speed, add the dry ingredients and the buttermilk mixture to the batter in thirds, alternating between each. Begin and end with the dry ingredients. Wipe down the bowl and beater as needed during this process and mix just until all ingredients are almost evenly incorporated, but still a bit streaky. Add the sprinkles in two parts, folding in by hand just until dispersed throughout the batter.
6. Divide the batter evenly between the three cake pans (using a kitchen scale if possible for accuracy) and smooth out the tops with an offset spatula.
7. Bake in the preheated oven for 30-35 minutes, rotating pans after 20 minutes, until a toothpick inserted into the center of each comes out clean. Allow the cakes to cool in pans on a wire rack for 10 minutes, and then turn over onto wire rack and remove parchment layer. Once completely cooled, wrap tightly in plastic wrap and freeze in a zip-top bag in the freezer for 30 minutes to 1 hour prior to decorating.

Cream Cheese Frosting

1. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and cream cheese together until light and creamy, stopping occasionally to wipe down the bowl and beater as needed.
2. With the mixer on lowest speed, slowly add the confectioner's sugar. Once all has been partially mixed in, increase speed to medium-high and continue to beat until light, fluffy, and smooth, again wiping down bowl and beater as needed.
3. Add the vanilla extract, almond extract, and salt and beat in until evenly incorporated.**

Assembly

1. Remove cakes from freezer and use a large serrated knife to level off tops as needed (but save the scraps to eat!) Place the first layer on a cardboard cake round set on a rotating cake stand, with strips of parchment placed partially underneath the cake on all sides to protect the cake board from excess frosting. (This will make it easier to get a clean final presentation).
2. Place a large dollop of frosting over the first cake layer and use an offset spatula to smooth into an even layer that covers the top surface of the cake. Place second cake layer on top and repeat. Top with third cake layer and then coat the entire cake with a thin layer of frosting to seal in lose crumbs (aka a crumb coat). Refrigerate cake for 30 minutes - 1 hour, until crumb coat has set.
3. Meanwhile, divide remaining frosting into 3 equal portions in separate bowls and use gel coloring(s) to tint each portion a different shade or color as desired. (Different shades of the same color or complimentary colors will work best for this technique.)
4. Remove cake from refrigerator and add a very large dollop of desired frosting color to top of cake. Use offset spatula to spread into a flat layer and push excess frosting over edges, working until top of cake is fairly smooth and neat. Add second frosting color to bottom 1/3 of cake and spread to cover. Finally, add last frosting color to middle 1/3 of cake to cover. Use offset spatula or palette knife to smooth out sides of cake while removing excess frosting and gently blending different colors to achieve ombré effect. Be careful not to work the cake so much that you loose the various shades of color.
5. Use offset spatula to wipe off any excess frosting around top perimeter of cake by pushing towards center at an angle and carefully pulling up, dipping spatula in hot water and wiping dry frequently as you go to help the frosting smooth out as much as possible. Once done, frosting should be smooth all around.
6. To decorate, use some of excess frosting to pipe large dollops around top perimeter of cake (I did this with an Ateco 827 open star tip ). Sandwich cookies with more of leftover frosting (I piped it on each with an Ateco 804 round tip ) and carefully press one into each dollop of frosting as pictured in photographs above. Sprinkle frosting dollops with rainbow jimmies.
7. Keep cake refrigerated until ready to serve. Store any leftovers in an airtight container in the refrigerator.