Make the Champagne Cake:
- Preheat oven to 350 degrees. Butter and lightly flour three 8″ round pans.
- In a medium bowl, whisk together the flour, baking powder and salt. Set aside.
- In bowl of stand mixer fitted with the paddle attachment, beat the butter and sugar on medium speed 4 minutes until light and fluffy.
- Add egg whites, one at a time, beating well after each addition and scraping down sides of bowl as needed.
- Add the vanilla extract and mix again.
- Gradually add the dry ingredients and the champagne, alternating, starting and ending with the dry ingredients. Mix until just combined, being careful not to over mix.
- Divide batter evenly between the three 8″ round pans.
- Bake for 23-25 minutes, until toothpick inserted into center comes out clean.
- Let cool in pans for 5 to 10 minutes, then remove to wire rack to finish cooling.
Make the Champagne Raspberry Reduction:
- Puree raspberries and strain to remove seeds.
- Place raspberry puree and champagne in a saucepan over med-low heat. Simmer, stirring occasionally at first and watching carefully as to not bubble over. All those champagne bubbles!
- Continue to simmer, while stirring, until reduced by half. You should have 3/4 cup remaining. Set aside to cool. This reduction is used in the buttercream and the glaze.
Make the Buttercream Frosting:
- In bowl of stand mixer fitted with the paddle attachment, beat butter and salt until creamy.
- Add in 1/2 cup raspberry reduction and vanilla. Mix well.
- Gradually add confectioner’s sugar 1 cup at a time, mix and scrape down sides of bowl as necessary.
- Mix until smooth.
- Remove 3 to 3 1/2 cups of frosting from the mixing bowl and set aside. This will be the plain pink frosting for the outside of the cake.
- Add 3 ounces fresh raspberries to remaining buttercream in mixing bowl. Mix on low speed for just a moment, until raspberries start to break up. You should have chunks of raspberry throughout. This will be the filling for between the cake layers.
Make the Drippy Raspberry Glaze:
- In a small bowl, combine raspberry reduction, confectioner’s sugar and vanilla. Whisk until smooth with no clumps.
- Add additional water or corn syrup until desired consistency for drizzling.
Assemble the Cake:
- Place one layer of cake onto serving plate or cake stand and top with about one cup of raspberry champagne filling (the buttercream studded with chunks of raspberries). Repeat with second cake layer, more filling and then last layer of cake.
- Crumb coat and frost cake with the reserved raspberry champagne frosting (the plain pink buttercream). Refrigerate for 20 minutes or until frosting is set.
- Drizzle glaze over the top with small drips overflowing the edge. Refrigerate for 20 minutes or until glaze is set. When ready to serve, garnish with whipped cream and additional raspberries.