In a 4 quart saucepan, melt butter and 1 ⅓ cup semi-sweet chocolate chips on medium low heat, stirring constantly so it doesn’t burn.

Remove from heat and let cool for 5-10 minutes, until lukewarm so eggs don’t scramble. 

In a medium bowl, mix together flour, cocoa powder, baking soda, and salt. Set aside.

Whisk sugar, eggs and vanilla extract into the saucepan with melted chocolate and butter.

Stir flour mixture into chocolate mixture until dough forms.

Fold in remaining 1 cup semi-sweet chocolate chips.

Let dough sit for 25-30 minutes. Dough will stiffen into a formable dough.

Preheat the oven to 350 degrees. Line a cookie sheet with parchment paper.

Scoop with a 2 inch cookie scoop (2 tablespoons) and roll into a ball. Pressing a thumb into the center of the ball, create a bowl in the dough and place 3 marshmallows in the center. Fold over dough to cover marshmallows. Pat into a ball, careful to keep the dough ball marshmallow side up.

Place the dough balls with marshmallow side up on a baking sheet, and bake for 9-10 minutes. They will appear dry around the edges, but slightly moist in the center (not gooey or wet).

Cool on the baking sheet for 5-6 minutes before removing gently to cool on a cooling rack.