Preheat the oven to 350°F and lightly grease three 12-count mini muffin pans.

In a large bowl, mix the Devil’s Food cake mix, eggs, oil, and black food coloring if using. Stir until smooth. If the dough is sticky, add flour a tablespoon at a time.

Scoop about ½ tablespoon of dough into each muffin cup and flatten gently.

Bake for 8–10 minutes until the edges are set but the centers remain soft.

While still warm, press the back of a 1-tablespoon measuring spoon into each cookie to form a cup, then cool completely in the pan.

Beat softened butter until creamy, then add powdered sugar, vanilla, and salt. Mix until smooth, adding milk a tablespoon at a time until the frosting is pipeable. Tint with green food coloring.

Pipe frosting into the cooled cookie cups to look like bubbling potion. Add green sprinkles, candy eyeballs, and Halloween sprinkles. Insert half a pretzel stick into each as a stir stick.

Arrange on a festive platter and serve at room temperature.