• Preheat the oven to 350°F. Line a 12-cup muffin pan with cupcake liners. Line a second pan with 2 liners – this recipe makes about 14 cupcakes.
•  Whisk the cake flour, baking powder, baking soda, and salt together. Set aside.
• Using a handheld or stand mixer fitted with a paddle attachment, beat the cannabutter on high speed until smooth and creamy – about 1 minute. Add the sugar and beat on high speed for 2 minutes until creamed together. Scrape down the sides and up the bottom of the bowl with a rubber spatula as needed. Add the egg whites and vanilla. Beat on medium-high speed until combined, then beat in the sour cream. Scrape down the sides and up the bottom of the bowl as needed. With the mixer on low speed, add the dry ingredients until just incorporated. With the mixer still running on low, slowly pour in the milk until combined. 
• Pour/spoon the batter into the liners – fill only 2/3 full to avoid spilling over the sides. Bake for 19-22 minutes, or until a toothpick inserted in the center comes out clean. Allow cupcakes to cool in the pan for 10 minutes, then remove from the pan to cool completely
• Fill the cupcakes: Using a sharp knife, cut a circle/hole into the center of the cupcake to create a little pocket about 1 inch deep. Remove this little piece and set aside. Pour sprinkles inside the hole. cut off a small piece enough to cover the hole. place on top. Repeat for all cupcakes and set aside.

FROSTING

•  With a handheld or stand mixer fitted with a paddle attachment, beat the cannabutter on medium speed until creamy – about 2 minutes. Add 4 and 1/2 cups confectioners’ sugar, the heavy cream, and vanilla extract with the mixer running on low. Increase to high speed and beat for 3 full minutes. Add up to 1/2 cup more confectioners’ sugar if frosting is too thin or another Tablespoon of cream if frosting is too thick.