• Preheat the oven to 350°F. Grease 4 pans, line them with parchment paper, then grease those papers, too.

Cake

• Whisk baking soda, baking powder, flour, and a pinch of salt in a bowl. Set that aside.
• Beat the unsalted butter at high mixer speed until creamy (a minute). Toss in the white sugar, mixing for 5 minutes until fluffy. Scrape the bowl's sides with a rubber spatula.
• Turn the mixer speed to medium-high, adding the eggs one at a time and mixing after each. Add vanilla and mix again.
• Switch the mixer to low and add your dry ingredients (from Step 2) in three batches, alternating with buttermilk. Start and end with a dry ingredient, mixing after each addition until JUST blended.
• Divide your batter into two bowls. Mix ⅓ cup of sprinkles in one bowl and some food coloring in another. Evenly spread or pour your cake batter into the prepared pans!
• Bake for 25 minutes (give or take); make sure the small toothpick poked in the middle comes out squeaky clean. Set the pans on the rack to cool off completely.
• Take a round, 6'' cookie cutter and punch a circle out of each cake. Grab a round 3'' cutter and make another cut inside that 6'' circle. You'll have four small 3'' circles, four medium 6'' rings, and four large 9'' outer rings.

Frosting

• Grab a bowl + mixer. Beat the unsalted butter at medium mixer speed until smooth (2 minutes). Let the mixer run low, then gradually add some confectioners' sugar, vanilla extract, salt, and cream. Crank the mixer speed to high and whip for 3 minutes.
• (Optional) Add confectioners' sugar (for too-thin frosting), cream (too-thick) or salt (too-sweet).
• Stack the vanilla cake: Start with a blue 9'' cake ring on your turntable. Drop in a Funfetti 6'' circle, followed by a baby blue circle in the center. Slather some frosting on top and smooth it out.
• Layer another 9'' circle filled with a 6'' blue circle and a small 3'' Funfetti in the center. Frost it all up. Keep repeating this with your remaining layers, then frost the entire thing. Optional: throw in more sprinkles.
• Refrigerate for 1-2 hours before slicing. Enjoy!