Preheat the oven to 325ºF. Prep the cupcake pan by adding cupcake liners followed by an Oreo in each cupcake mould.

In a stand mixer using the paddle attachment, cream together the butter, coconut oil, sugar, baking powder, baking soda, and salt.

Start by mixing on low to moisten before increasing the speed to medium-high until the mixture is pale and fluffy, about five minutes. Be sure to scrape down the bottom and sides of the mixing bowl about halfway through mixing to avoid any lumps from forming.

Slowly add the egg whites, followed by the vanilla, mixing well after each addition.

Alternatively add 1/3 of the cake flour followed by 1/3 of the buttermilk, mixing on low after each addition, until all of the cake flour and buttermilk have been added and a smooth batter forms.

Pour the batter over the Oreos, filling almost to the top. Bake for 20-22 minutes, or until a toothpick inserted comes out clean or the cupcakes reach 200ºF in the center.

Allow the cupcakes to cool for at least 30 minutes before frosting.

In a stand mixer using the paddle attachment, beat the softened butter on high speed for 3 minutes, or until the butter is creamy and slightly pale.

Add half of the powdered sugar, vanilla, and kosher salt. Mix until the ingredients are mostly incorporated.

Add the rest of the powdered sugar. Scrape down the sides and bottom of the mixing bowl to prevent any lumps from forming.

Add the heavy cream and mix until the buttercream is completely smooth.

Adjustments: If the buttercream is too sweet you can add a pinch of kosher salt to reduce the sweetness. If the buttercream is too thin, you can add more powdered sugar, 1/4 cup at a time. If the buttercream is too thick, you can add heavy cream, one tablespoon at a time.

Add the crushed Oreos and mix until they are evenly dispersed throughout the buttercream.

Frost the cupcakes and enjoy!