¾cupbuttermilk, room temperature and shaken(see note at the end of the recipe)
2teaspoonsvanilla extract
1largeegg, room temperature
2largeegg whites, room temperature
⅓cupvegetable oil
1teaspooncinnamon
(1)15 to 16-ounce boxwhite cake mix
Frosting
3stickssalted butter, softened
1teaspoonvanilla extract
6tablespoonsapple cider mix
1pinchsalt
6tablespoonsheavy cream
5 - 5 ½ cupspowdered (icing) sugar
Instructions
Cupcakes
Preheat oven to 325°F. Place cupcake liners into a muffin pan.
Add the sour cream, buttermilk, vanilla, eggs, and vegetable oil to a large mixing bowl. Whisk until smooth.
Place the cake mix and cinnamon into a sifter or wire-mesh strainer and sift the dry ingredients into the wet ingredients. Stir until smooth but not overmixed. Do not skip sifting the cake mix to prevent lumps in the batter.
Place the cake batter into the cupcake liners using a cookie scoop or large spoon, filling them 1/2 to 2/3 full.
Bake for 15-18 minutes or until the cupcakes are lightly browned and a toothpick inserted into the middle comes out clean or with crumbs. Do not overbake. Remove the cupcakes from the oven. After a couple of minutes of cooling, transfer them to a cooling rack before frosting.
Frosting
Beat the butter, vanilla, apple cider mix, salt, and cream with an electric mixer until creamy.
Place the apple cider mix, salt, vanilla, and cream into a small bowl. Stir until the apple cider mix dissolves. Pour into the bowl with the butter and beat until smooth.
Add the powdered sugar, one cup at a time, beating between each addition. If the frosting is too stiff, add more cream. If too soft, add more sugar.
Use a piping bag and a large star tip to pipe frosting onto the cupcakes. Pipe a circle of frosting around the outside of the cupcake top. Continue circling, moving closer to the center. This will make the frosting taller in the center of the cupcake.
Notes
Buttermilk
Buttermilk can separate into curds and whey after it sits for a while. Always vigorously shake the buttermilk container before using it to remix any separation of the milk.
Do Not Overmix the Batter
Do not overmix the batter when you add the dry cake ingredients to the wet ingredients. Overmixing the batter produces gluten, making the cupcakes tough and chewy.