Preheat oven to 350 degrees F.
Line muffin tins with cupcake liners.
Add your Kit Kat bars into a ziploc bag seal closed.
Using a rolling pin crush your candy bars.
In a large bowl add together all the dry ingredients and sift.
In a medium bowl, add all the wet ingredients, whisk to combine.
Add your egg and whisk the egg into the wet ingredients.
Using a stand mixer, add your dry ingredients.
Add the wet ingredients to the dry ingredients.
Mix for 2 minutes on medium speed and scrape down the sides and bottom of bowl.
Divide evenly among the cupcake liners.
Bake for 13 minutes or until a toothpick inserted in the center comes out clean.
Allow cupcakes to cool completely.
In a stand mixer use a paddle fixture add the butter mix medium speed for about 2-3 minutes.
Butter will be light and creamy.
Add the powdered sugar, vanilla extract, and heavy cream to the butter.
Begin to mix on low speed.
Add the crushed Kit Kats and increase speed to medium-high and whip for 6 minutes.
Chop remaining Kit Kats into quarters.
Drizzle fudge on top of the cupcakes.
Garnish the cupcakes with the Kit Kats.