01 -
Preheat oven to 350°F and lightly grease three 12-cup mini muffin pans.
02 -
Combine Devil's Food cake mix, eggs, canola oil, and black food coloring if using in a large bowl; mix until fully incorporated.
03 -
Scoop about 1/2 tablespoon of dough into each muffin cup and gently flatten the surface with fingertips.
04 -
Bake for 8 to 10 minutes until edges are set. Remove from oven and immediately press a tablespoon into each cookie to create an indentation. Let cool completely in pans.
05 -
Beat softened butter in a medium bowl until creamy. Gradually add powdered sugar, vanilla extract, and salt. Incorporate milk one tablespoon at a time until smooth and pipeable. Tint with green food coloring as desired.
06 -
Pipe the buttercream into each cooled cookie indentation to simulate bubbling potion.
07 -
Top with green sprinkles, Halloween sprinkles, and candy eyeballs. Break pretzel sticks in half and insert one half into each cookie as a stir stick.
08 -
Arrange cookies on a platter and serve promptly.