Cream together ½ cup of softened butter and 1 cup of granulated sugar until light and fluffy. Add 2 large eggs one at a time and 2 teaspoons of vanilla extract, mixing until smooth.

In another bowl, whisk together 1 ½ cups of all-purpose flour, ½ cup of unsweetened cocoa powder, 1 teaspoon of baking soda, and ¼ teaspoon of salt. Gradually add this to the wet mixture until just combined.

Fold in 1 cup of mini or regular marshmallows, ensuring they are evenly distributed throughout the dough.

If the dough is too sticky, refrigerate for about 30 minutes.

Preheat the oven to 350°F (175°C). Roll tablespoons of dough into balls and place them on ungreased baking sheets, leaving 2 inches between each.

Bake for 12-15 minutes, rotating the sheets halfway through, until edges are set and centers remain soft.

Let the cookies cool on baking sheets for about 5 minutes, then transfer to wire racks to cool completely.