Beat the butter and sugar together until smooth and light. Add the egg, vanilla and mix completely.

Stir in the flour, baking powder, salt until mostly combined. **If you’re using cut-up regular marshmallows, toss them with a tablespoon of the flour first to help them stay separated.**

Add the marshmallows and chocolate and mix until dough forms.

Scoop onto lined baking sheet by 2T balls. Sprinkle with coarse salt if you like. Refrigerate the tray while the oven heats to 325øF.

Bake 12-14 minutes until puffed and the edges are browned. The marshmallows will be slightly  toasted on the outside. Let cool on baking sheet until cool enough to handle. Then transfer to rack to cool completely.

Store in an airtight container at room temperature for several days.