Gluten-Free Champagne Cupcakes With White Chocolate Buttercream

*gluten-free all-purpose flour ((I like Pillsbury gluten-free. Not all gluten-free flours are created equal. You may experience different baking results depending on the gluten-free flour blend you choose.))

teaspoon  xanthan gum  ((Leave out if your flour already contains it.))

sugar

baking soda

gluten-free baking powder

salt

butter (, room temperature)

egg whites

pure vanilla extract ((I like Watkins clear vanilla extract for white cupcakes))

gluten-free almond extract

sour cream

champagne (, not sparkling wine, or ginger ale for a non-alcoholic version)

gluten-free sprinkles ((optional))

butter (, room temperature (two sticks of butter))

gluten-free white chocolate chips (, melted)

powdered sugar

pure vanilla extract ((I like Watkins clear vanilla extract for white cake))

heavy whipping cream

of  salt