01 -
Using a mixer, whip up the softened butter until it turns light in color and fluffy, about 2-3 minutes. Slowly add powdered sugar a bit at a time, keeping your mixer on low. Once combined, pour in the champagne, vanilla, and salt. Beat everything on medium-high speed for about 3-5 more minutes until it’s super creamy. Add pink coloring at the end if you’re using it.
02 -
Set your oven to 350°F. Line three six-inch cakes pans with parchment paper. Lightly butter and flour them or use a good baking spray.
03 -
In a separate bowl, stir together your measured flour, salt, and baking powder. Whisk until it’s well blended.
04 -
Put your butter and sugar into a mixing bowl and beat until fluffy, around 2-3 minutes. Add the vanilla. Add egg whites one at a time, making sure each is mixed in well. Pause to scrape the bowl often to keep things even.
05 -
Add the dry ingredients to the wet batter in turns with the champagne—flour first, then champagne, and repeat until all has been used. Don’t overmix. If you’re using pink color, stir it in after the second round of flour.
06 -
Divide the batter between the three pans evenly and smooth the tops out. Pop them into the oven for 25-30 minutes. They’re done when a toothpick or skewer comes out mostly clean with just a few crumbs. Let them cool in the pans for 10 minutes, then turn them out onto cooling racks to cool fully.
07 -
Make sure your cakes are completely cool before stacking and frosting them. Spread the fluffy champagne buttercream between each layer and all over the outside. If you’d like, drizzle white chocolate or add marshmallows and strawberries dipped in chocolate on top.