Preheat oven to 350 degrees F.
Grease 3 round 9" cake pans and then coat with flour. I do this by placing ~1/4 cup of flour into each pan and moving the cake around so the flour coats the grease evenly. You want to make sure all the sides are coated so the cake doesn't stick!
In a large bowl, combine flour, baking powder, baking soda, and salt and whisk well to combine. Set aside.
In a large bowl with electric mixer, beat butter until light and fluffy - about 2 minutes.
Add sugar and beat until creamed together, a good 4-5 minutes.
Add 4 eggs (don't add the 2 egg whites quite yet - they will be added later), one at a time, beating until full combined and scraping the edges as needed.
Add the vanilla and almond extracts and beat until well combined.
Place the electric mixer on low speed and add the flour mixture in three additions, alternating with additions of the buttermilk. Mix until just combined and don't overmix.
In a separate bowl, beat the egg whites until white, foamy, and soft peaks form.
Gently fold egg white mixture into cake batter, then fold in sprinkles.
Evenly divide batter between the three prepared cake pans.
Bake in preheated oven for 24-26 minutes, until cake tester comes out clean and edges are slightly golden.
Let cool completely in the pans.
To make the frosting:
Beat butter until light and fluffy, about 2 minutes.
Add powdered sugar in increments, and beat for another 2 minutes.
Add extracts, heavy cream, and salt and beat until well combined.
To assemble the cake:
Use a serrated knife to slice off a thin layer of cake so the tops are flat.
Place one cake on cake stand and top with layer of frosting.
Place another layer on top and repeat with remaining 2 layers.
Spread the rest of the frosting over the top and sides of the cake.
Decorate with sprinkles, candles, or additional piped frosting.
Cut and enjoy!
*I place my eggs in warm water for about 15 minutes to bring them to room temperature faster