White Wedding Cake Cupcakes

Ingredients (9)

• One 15.25-ounce box white cake mix
• 1 cup all purpose flour
• 1 cup granulated white sugar
• 3/4 teaspoon salt
• 1 1/3 cups water
• 2 tablespoons vegetable or canola oil
• 1 teaspoon vanilla extract
• 1 cup sour cream
• 4 large egg whites