Thanks @melaimomagwork! I'm so glad you like this post. Here's the recipe.

Ingredients

Muffin Batter:
1/2 cup (1 stick) butter, melted
2/3 cup sugar
1/2 teaspoon salt
1 1/2 teaspoons baking powder
1/2 cup, about 8, egg yolks (or 3 whole eggs)
1 cup melted ice cream, any flavor (use your own judgment on flavors, anything vanilla or chocolate based should be good, but I'd probably hold off one like cotton candy or peppermint.)
1 cup whole milk
1 teaspoon vanilla extract
1 1/3 cups all purpose flour
1 cup mini-marshmallows (I used homemade
2/3 - 1 cup chopped candy bar pieces or chocolate chips
Crumb Topping:
1/3 cup butter (around 6 tablespoons), softened
3 tablespoons bacon grease (or more butter if you're boring)
1 cup brown sugar, packed
1 teaspoon vanilla extract
1/4 teaspoon salt
1 cup all purpose flour
1 cup crumble potato chips
1 cup crushed pretzel pieces
Instructions

1. Pre-heat oven to 350 degrees F (180 C) and line 2 muffin pans with 18 to 20 paper liners.
2. Whisk together butter, sugar, salt, and baking powder until smooth. Add egg yolks, melted ice cream
   milk, and vanilla and stir to combine. Add flour, then stir in marshmallows and candy bar pieces.
   Divide the batter into cups and bake for about 10 minutes.
3. While those bake, mix butter, bacon grease, and sugar, vanilla, and salt together in a medium bowl until combined. Add flour and mix until it forms a dough, then stir in chips and pretzels. Remove pans from the oven after 10 minutes and sprinkle the crumb topping over each one (I piled it pretty high.) Return pans to oven and bake for 25 to 30 minutes until a toothpick comes out clean.