Yield: 6-inch cake and 3 dozen mini doughnuts
Preheat oven to 350 degrees F. Line two 6-inch round cake pans with parchment. Lightly grease and set aside.
Whisk together cake flour, baking powder and salt. Set aside. In a small bowl, combine milk and vanilla. Set aside.
In the bowl of stand mixer fitted with a paddle attachment, cream butter. Add sugar and mix until smooth. On low speed, add eggs one at a time, making sure each egg is incorporated before adding the next one. Scrape down bowl as needed to ensuring thorough mixing.
Add a third of flour mixture into mixing bowl. Mix on low speed and add half of vanilla milk mixture. Add another third of flour mixture, following with remaining half of vanilla mix mixture. Add last third of flour mixture and mix until there are no longer any dry streaks of flour. Fold in confetti sprinkles until evenly distributed.
Evenly divide cake batter between the two prepared cake pans. Level cake as needed using a mini offset spatula, or the back of spoon. Bake for 30-35 minutes until toothpick inserted in center of cake comes out clean. Let cool in pan for 5-7 minutes before unmolding from cake pan. Allow cakes to cool to room temperature on a wire rack.
Cream butter until smooth. Add espresso powder and salt and mix until throughly combined. Add sifted powdered sugar one cup at a time. Follow with heavy cream. Add pink food gel coloring until desired color is achieved.
*If buttercream is too thin, add additional powdered sugar 1/4 cup at a time until desired consistency is achieved. If buttercream is too thick, add heavy cream 1/2 tablespoon at a time until desired consistency is achieved.
Preheat oven to 350 degrees F. Grease mini doughnut pan and set aside.
Sift together flour, baking powder, salt, nutmeg, and cinnamon. Set aside.
In a large bowl, beat together sugar and egg until thick and light in color. Add dry ingredients to sugar egg mixture. Mix until combined.
Whisk together oil, milk, and vanilla. Add to batter in two additions until incorporated. Let batter stand for 3-5 minutes to slightly thicken.
Transfer batter to pastry piping bag. Pipe batter into prepared doughnut pan filling each mold about half full. Alternatively, spoon batter into doughnut pan. Bake for 10-12 minutes. Let cool in pan for 2 minutes before unmolding. Let cool on wire rack until ready to decorate.
Combine confectioners sugar, maple syrup, and milk. Stir until smooth. Dip one side of cooled mini doughnut into glaze. Immediately top with confetti sprinkles. Place glazed doughnut on wire rack and allow glaze to set.
Slice each funfetti cake in two layers. You should end up with four layers of cake. Place one layer on a cake stand or a cake plate.
Combine simple syrup and whiskey. Lightly moisten the cake layer with syrup using a pastry brush.
Spread a thin layer of coffee buttercream over moistened cake. Place another cake layer on top. Moisten with syrup and top with frosting. Repeat until you finish with the top layer. Crumb coat the cake by spreading a thin layer of buttercream on the sides of the cake. Place in the fridge for 15-30 minutes to allow buttercream to slightly harden.
Meanwhile, dip doughnuts in glaze and top with sprinkles.
Coat the cake in another thin layer of buttercream. Garnish the top of the cake with confetti sprinkles. Arrange glazed doughnuts around the bottom of the cake. Use remaining buttercream to help doughnuts stick to cake. Keep cake stored in the fridge until ready to serve. Let cake sit at room temperature for at least 30 minutes before serving to allow cake to soften.