Gluten Free Champagne Cake recipes

Name: Gluten Free Champagne Cake recipes
Ingredients: 1 3/4 cup (245 g) basic gum-free gluten free flour (162 g superfine white rice flour + 54 g potato starch + 29 g tapioca starch/flour); 1/4 teaspoon xanthan gum; 2 tablespoons (18 g) cornstarch (can’t have cornstarch? try arrowroot and let us know how it goes!); 1 teaspoon baking powder; 1/2 teaspoon baking soda; 1/2 teaspoon kosher salt; 1 cup (200 g) granulated sugar; 1 egg (60 g, out of shell), separated + 1 egg white, at room temperature; 8 tablespoons (112 g) unsalted butter, at room temperature; 2/3 cup (5 1/3 fluid ounces) sparkling wine (can substitute ginger ale for an alcohol-free version); 1 1/2 cups (300 g) granulated sugar; 1/2 teaspoon cream of tartar; 1/4 cup sparkling wine (can substitute ginger ale for an alcohol-free version); 5 egg whites (150 g total); 24 tablespoons (336 g) unsalted butter, cubed and kept cool (but not cold); 1/8 teaspoon kosher salt