In a mixing bowl, combine warm water, sugar, and yeast. Let it sit for 5-10 minutes until frothy.

Add flour, salt, and melted butter to the yeast mixture. Mix until a dough forms.

Knead the dough on a floured surface for about 5 minutes until smooth.

Place the dough in a greased bowl, cover with a kitchen towel, and let it rise in a warm place for 30 minutes or until doubled in size.

Preheat the oven to 375°F (190°C).

Punch down the risen dough and divide it into 8 equal pieces.

Flatten each piece and place a marshmallow in the center. Pinch the dough around the marshmallow to seal it.

Place the rolls seam-side down on a baking sheet. Let them rise for another 10 minutes.

Bake for 15-20 minutes until golden brown. Cool slightly before serving.