Rich and fudgy, these dark chocolate marshmallow cookies are stuffed with gooey marshmallows and a hint of espresso for a hot chocolate-inspired treat!
Cream the butter, light brown sugar, and granulated sugar together until light and fluffy, about 2 minutes.
Mix in the egg, egg yolk, and vanilla extract until just combined.
Mix in the flour, cocoa powder, espresso powder, salt, baking soda, and baking powder until just combined.
Cover the bowl and chill the chocolate cookie dough in the fridge for 1 hour.
Preheat the oven to 350 F/180 C.
Scoop 8 dough balls with a standard cookie scoop (two tablespoons) onto a parchment-lined baking tray. Re-cover the bowl of dough and keep it in the fridge while the first tray bakes!
Cut 4 marshmallows in half lengthwise.
Then lightly flatten each dough ball. Place one marshmallow half in the center of the dough. Fold the dough around it so it’s completely encased.
Roll the cookies in the cane sugar, leaving a thicker pile of sugar on top of the cookie.
Bake the cookies for 8-10 minutes, or until the puffy tops are cracked.
Remove and let the tray cool on a wire cooling rack. The marshmallow may make them stick to the pan, use a spatula if needed to keep them from tearing.
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Notes
*Measure your flour properly. This is my #1 baking tip! Do not ever scoop a measuring cup into your flour as this always leads to using too much flour. Instead, use the spoon-level method. This means fluffing the flour first, then spooning it into your measuring cup/spoon. For the BEST results, use a kitchen scale!*Put the marshmallow on its side. Once cut, the marshmallow should be placed on its side, not flat (don't put it cut side down). This will keep the marshmallow from oozing out of the sides.Storage: Store any baked cookies in an airtight container with parchment paper in between stacks to keep them from sticking. They will stay soft for 1-2 days at room temperature!Freezing: The dough balls can be frozen, however, they will need an extra 1-2 minutes of baking time and the marshmallow will disappear more into the dough.