Orange Dreamsicle Cupcakes

Name: Orange Dreamsicle Cupcakes
Ingredients: 1 1/2 cups all-purpose flour; 1 1/2 teaspoons baking powder; 1/2 teaspoon salt; 2 large eggs, separated; 1 stick unsalted butter, at room temperature; 1 cup granulated sugar; 1 tablespoon finely grated orange zest; 1 teaspoon orange oil (available at specialty stores); 1/2 cup fresh orange juice (from 2 oranges); 2 sticks unsalted butter, at room temperature; 1 teaspoon pure vanilla extract; 4 cups confectioners' sugar, sifted; 2 to 3 tablespoons whole milk or heavy cream; Orange and/or white sanding sugar, for topping; Orange gummy candies, for topping