Chocolate marshmallow cookies are fudgy and chewy double chocolate sugar cookies filled with gooey marshmallows, rolled in a sweet, crunchy sugar coating.
In a small bowl, melt the butter and cool in the fridge for about 15 minutes. In another bowl whisk together the flour, baking powder, baking soda, cornstarch and salt until well combined.
Whisk in the egg, egg yolk, maple syrup, vanilla extract and cocoa powder until smooth and well combined.Stir the dry ingredients into the wet until just combined.
Pour the sugar for rolling into a small bowl and set aside.Preheat the oven to 350 F (177 C) for about 20-30 minutes before baking the cookies. Line a large baking sheet with parchment paper. Allow the dough to rest while the oven preheats for 30 minutes or transfer to the fridge to store for longer.
Using a large cookie scoop (3 tablespoons, 45 ml), scoop the chocolate sugar cookie dough into the palm of a clean hand. Gently press the dough into a disk. Insert 6 - 7 mini marshmallows or one regular sized marshmallow into the center. Gently lift the sides up and around the marshmallows.
Roll the cookie dough ball into sugar and place the cookie dough balls onto the lined baking sheet about 3 inches (8 cm) apart. Bake at 350 F (177 C) for 12 -14 minutes.
Cool the chocolate mini marshmallow cookies on the baking sheet for 5 minutes. Then transfer to a cooling rack to cool completely to room temperature and enjoy!