Preheat your oven to 350°F (175°C). Prepare two 8-inch round cake pans by greasing them with butter and lining the bottoms with parchment paper.

In a large mixing bowl, cream together 1 cup of softened unsalted butter and 1 ¾ cups of granulated sugar using an electric mixer for about 3-5 minutes until light and fluffy.

With the mixer running, add 4 large eggs one at a time. Once all the eggs are mixed in, add 1 cup of sour cream, mixing until smooth.

In a separate bowl, whisk together 2 cups of all-purpose flour, 1 teaspoon of baking powder, ½ teaspoon of baking soda, and ¼ teaspoon of salt.

Mix 1 teaspoon of vanilla extract with 1 cup of prosecco. Gradually add the dry mixture to the creamed mixture, alternating with the prosecco mixture.

Divide your batter between the prepared pans and smooth the tops. Bake for 35-40 minutes, until a toothpick comes out clean.

Let the cake cool in the pans for about 5-10 minutes, then invert onto a wire rack to cool completely.

In a mixing bowl, combine 1 cup of softened butter with 3-4 cups of powdered sugar and beat until fluffy. Add 2-4 tablespoons of prosecco to achieve desired consistency.

Once the layers are cooled, frost between layers and on the top and sides of the cake.