These treats bake in a mini muffin pan, no campfire or grill needed. They're more buttery than the classic s'mores, and less messy. You're likely to have crumbs instead of gooey marshmallows on your fingers and clothes.
Preheat oven to 350 degrees (F).
Combine the crumbs and sugar in a medium bowl. Stir in the melted butter and mix until blended.
Lightly grease 24 cups (1-3/4-inch diameter) in a mini muffin pan.
Divide the crumbs among the cups. Press the crumbs down and around the sides with a tart tamper, a spoon, or your fingers.
Bake 6 - 7 minutes.
Remove the pan from the oven. Put one chocolate rectangle** in each cup and top with a marshmallow, cut side down, on top of it. Return pan to the oven for 3 minutes or until the marshmallows are softened. To brown the marshmallows, put the pan under the broiler for a minute.
Cool the pan on a rack for 15 minutes. Carefully lift each tartlet from it's cup. Serve warm immediately or serve at room temperature after the tartlets have cooled down.
*Or substitute 2 - 3 teaspoons mini chocolate chips for the chocolate bars. I found that the tartlets were easier to remove from the pan and stayed intact using the chips.
**I used 2 chocolate rectangles since my mini-muffin pan has a large diameter for each cup.
If marshmallows cool too much making it difficult to remove tartlets from pan, place the pan back into the warm oven for a minute or two to soften edges.
Store leftover marshmallows in a freezer-safe ziplock bag and place in the freezer to keep them fresh.