Your favorite devils food cake batter
Mix devil's food (chocolate) cupcake batter.
Fill muffin tins only half full.
Push a marshmallow in the center. (It will stick up a bit)
Bake as normal.
The marshmallow toasts on top, melts, bubbles all over, and leaves a cavity in the middle. (a cauldron! :))
You can fill the cavity with pistachio pudding, ice cream, frosting, candy, whipped cream, peanut butter, Fluff, jelly.... anything. or just leave them plain.
I have also tried putting other things besides marshmallows in the center before baking... a mini Reeses peanut butter cup (yum), Rolo carmels, chocolate chips, a spoon of fudge ice cream topping, Hershey kiss... most of these sink and melt during baking and make a fudgy bottom.
LexiconBel's recipe was taken with permission.