Preheat oven as per directions on the box and place 24 cupcake liners into a cupcake pan. Set aside.
Make the cake batter according to the box instructions.
Use an ice cream scoop to evenly divide the batter between the cupcake liners
Place in oven and bake for the time directed or until an inserted toothpick comes out clean.
Remove from oven and allow to cool in the pan for 5 minutes before transferring to a wire rack to cool completely before frosting.
To make the frosting, use an electric stand or handheld mixer and add the butter, powdered sugar, cream, and vanilla to the mixing bowl.
Mix on medium speed until combined, then add black food coloring gel and continue to mix to desired shade. Frosting should be creamy and smooth.
Using a medium ice cream scoop, scoop frosting onto each of the cupcakes.
Use a knife or angled spatula to flatten slightly and spread into a thick disk.
Pour the Halloween sprinkles into a deep bowl.
Dip the top of the cupcake frosting into the sprinkles.
To make the chocolate ganache, place the chocolate chips into a medium bowl.
Place the cream in a heavy-based pan over medium heat and bring to the boil.
Pour the hot cream over the chocolate chips and let sit for 2 minutes and then mix until smooth and combined.
Pour the ganache into a disposable piping bag and cut off the tip. (Or use a food bag with the corner snipped off.)
Pipe a thick circle of ganache in the center of the frosting.
Using 6 pieces of Twix per cupcake, pile on the pieces adding more ganache to stick in place. Enjoy and Happy Halloween!