To make the funfetti cake: Preheat the oven to 350°F (180°C). Spray three 8-inch round cake pans with nonstick cooking spray, line the bottom of the pans with parchment paper, and set aside.
In a large mixing bowl, whisk the cake flour, baking powder, baking soda, and salt together until well combined. Set aside.
In a large mixing bowl or measuring cup, whisk the buttermilk, oil, vanilla extract, and almond extract together until well combined. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment or in a large mixing bowl using a handheld mixer, beat the butter on low speed until smooth, then slowly mix in the granulated sugar.
Once all of the sugar is added, increase to medium speed and continue mixing for another 4 to 5 minutes or until the mixture is light and fluffy.
Mix in the eggs, one at a time, making sure to stop and scrape around the bottom and sides of the bowl after each egg.
Add the dry ingredients in three additions alternating with the buttermilk mixture (begin and end with the dry ingredients) on low speed. Mix in each addition until just combined, making sure not to over mix the batter.
Use a rubber spatula to scrape around the bottom and sides of the bowl to ensure that everything is well combined, then gently fold in the sprinkles.
Evenly divide the batter between the three prepared cake pans and spread around into one even layer.
Bake for 25 to 30 minutes or until a toothpick inserted into the center of the cakes comes out clean. Remove from the oven and allow to cool in the pans for about 20 minutes. Slide a knife around the outside of the cakes, then carefully remove the cakes from the pans, and transfer to a wire rack to cool completely.
To make the Swiss meringue buttercream: Add the egg whites, granulated sugar, and salt to a large heat-proof bowl and whisk until well combined.
Place the bowl over a pot of simmering water, making sure the bottom of the bowl does not touch the water. Whisk constantly until the mixture registers 160°F (71°C) on a digital thermometer (the amount of time will vary so I recommend using a thermometer here).
Remove the bowl from the heat and transfer the mixture to the bowl of a stand mixer fitted with the whisk attachment. Beat the mixture on medium-high speed until stiff glossy peaks form (about 10 to 15 minutes). If the outside of the bowl is still warm to the touch at this point, allow it to cool (or transfer to the refrigerator for 10 to 15 minutes) before proceeding with the next step.
Switch from the whisk attachment to the paddle attachment. With the mixer on medium-high speed, add the butter 1 tablespoon at a time, making sure each tablespoon of butter is fully mixed in before adding the next tablespoon. Once all of the butter is added, continue mixing if needed until the mixture is thick, smooth, and creamy.
Scrape down the sides of the bowl, add the vanilla extract, and continue mixing on medium speed until fully combined (about 20 to 30 seconds).
Adjust the mixer to the lowest speed and continue mixing for 5 to 7 minutes to remove air bubbles. If needed, use a rubber spatula to beat out any remaining air bubbles.
To assemble the cake: Level the tops of each cake with a knife or cake leveler. Place one of the cakes on a cake stand, top with ¾ cup - 1 cup of frosting, smooth it out into one even layer, repeat with the second layer and another ¾ cup - 1 cup of frosting, place the third layer on top, and use the remaining frosting to frost the top and sides of the cake.