In a light-colored saucepan, melt 1 cup of unsalted butter over medium heat, stirring frequently. Watch closely as it transforms to a golden brown color, releasing a nutty aroma.

Preheat your oven to 350°F (175°C) and grease your cake pans (three 8-inch or four 7-inch). In a large mixing bowl, whisk together 2 cups of all-purpose flour, 1 ½ cups of granulated sugar, 1 tablespoon of baking powder, and ½ teaspoon of fine salt.

Gradually blend in the cooled brown butter until the mixture resembles coarse sand, ensuring even distribution of that delicious nutty flavor.

To the flour mixture, add 4 egg whites, 1 cup of full-fat sour cream, ⅓ cup of vegetable oil, and 2 teaspoons of vanilla extract. Mix until just combined and smooth.

Divide the batter evenly between the prepared cake pans. Bake for 33-35 minutes, or until a toothpick comes out clean with a few moist crumbs.

Once baked, let the cakes cool for about 10 minutes. Carefully transfer to wire racks to cool completely.

In a mixing bowl, beat together ½ cup of cooled brown butter and 8 ounces of cream cheese until creamy. Gradually add 4 cups of powdered sugar and ¼ cup of heavy whipping cream, mixing until spreadable.

Once the cake layers have cooled, frost each layer and coat the entire outer layer with frosting for a beautiful finish.