Preheat oven to 350F and line a 12-cup muffin tin with paper wrappers. Set aside.
Place butter and sugar in a large bowl (or a stand mixer fitted with paddle attachment) and use an electric mixer to beat on medium speed 2-3 minutes until smooth and creamy.
Add eggs and egg yolks one at a time to butter mixture while beating constantly on medium speed, beating well after each addition. Mix in vanilla until smooth.
In a medium bowl, combine flour, cornstarch, baking powder, and salt. Working in increments, fold 1/3 flour mixture and 1/3 of buttermilk into butter-sugar mixture until smooth and repeat 2 more times until all the flour and buttermilk has been added and batter is smooth. Fold in coconut.
Fill muffin cups 3/4 full of batter and smooth tops. Bake cupcakes at 350F 20-25 minutes until a toothpick inserted in center of cupcake comes out clean. Cool cupcakes completely on a wire cooling rack.
Cream Cheese Frosting
Place cream cheese and butter in a large bowl (or a stand mixer fitted with paddle attachment) and use an electric mixer to beat on medium speed 2-3 minutes until creamy.
Add powdered sugar, half and half, and vanilla to cream cheese mixture and beat an additional 3-4 minutes until frosting is completely smooth and creamy. Refrigerate frosting until ready to frost cupcakes.
Allow frosting to soften to room temperature if you refrigerated it before frosting cupcakes. Frost cupcakes and garnish with toasted coconut. Store cupcakes in refrigerator until ready to serve. Enjoy!
Notes
Storing InstructionsStore cupcakes in refrigerator up to 4 days.