Prepare the Cupcakes -Preheat oven to 350 degrees and move rack to the middle of the oven. -Add cupcake liners to cupcake tin -Whisk together egg whites, champagne, vanilla, and food coloring until well combined -Mix flour, sugar, baking powder, and salt until combined on low speed -Add butter one piece at a time -Add all but 1/2 cup of egg white mixture and mix until combined -Increase speed to medium-high and beat for 1 minute -Add remaining egg white mixture in slow stream -Scrape down bowl and be sure everything is combined
– Bake Cupcakes: – Fill each cupcake liner ⅔ of the way up. – Bake until toothpick inserted in center cupcake comes out clean, 18 to 20 minutes, rotating pans halfway through baking. – Let cupcakes cool in tins on wire rack for 10 minutes. – Remove cupcakes from tins and let cool completely on wire rack, about 2 hours.
– Melt the White Chocolate for the Frosting: – In the top of a double boiler or a bowl set over simmering water (make sure the bottom of the bowl does not touch the water and that you keep your burner set on low), melt the white chocolate, stirring every minute or so. – Once fully melted, remove it from the heat and allow it to cool, about 5 minutes. – Dip your finger in to test the temperature, once it’s cool enough to touch, you can use it in the next step. If it’s too hot, it will melt the butter in your buttercream which is not what you want.
– Prepare the Frosting: – In the bowl of a stand mixer or using a hand mixer, beat the butter until light and fluffy, 3-5 minutes. – Sift in the powdered sugar and salt and add the vanilla. – Beat until well blended. Beat in slightly cooled white chocolate with the mixer speed on low, then beat at medium-high speed for 1-2 minutes until smooth and fluffy. – Top your Cupcakes: – Pipe or spread frosting onto cooled cupcakes. – With a slotted spoon, remove a few pieces of strawberries from champagne bath and place on top of each cupcake. – Add sprinkles and serve.