- 8oz (1 Cup) Salted Butter, at room temperature
- 150 grams (3/4 Cup) Light Brown Sugar
- 100 grams (1/2 Cup) Granulated Sugar
- 1 Teaspoon Pure Vanilla Extract
- 1 Large Egg + 1 Large Egg Yolk, at room temperature
- 250 grams (2 Cups) All-Purpose Flour
- 75 grams (3/4 Cup) Dutch Process Cocoa Powder
- 1/2 Teaspoon Baking Powder
- 1/2 Teaspoon Baking Soda
- 1/2 Teaspoon Salt
- 2 Teaspoons Cornstarch
- 1/2 Teaspoon Espresso Powder
- 100 grams (1 Cup) Mini Marshmallows
- In the bowl of an electric mixer combine the butter, brown sugar, and granulated sugar. Beat until light and fluffy and the color has lightened. About 2-3 minutes.
- When the butter/sugar mixture has lightened add the whole egg, additional egg yolk, and vanilla extract then mix on medium speed for another 2 minutes, making sure to scrape down the sides of the bowl.
- In a large bowl sift together flour, cocoa powder, baking soda, baking powder, salt, cornstarch, and espresso powder.
- Slowly add the dry mixture and mix until just combined.
- Using a medium cookie scoop, scoop the batter into 2 tablespoon size balls then flatten them in your hand and add about 5 mini marshmallows then pinch the cookie dough to seal the marshmallows in and roll the dough in your hands to make a ball. Place the cookie dough balls on a parchment-lined baking sheet or plastic container and chill in the fridge for 30 minutes or freezer for 15 minutes before baking. I found if I chilled them for longer the marshmallow didn't melt as nicely so be brief with the chilling!
- Preheat oven to 350F/180C and place cookies on a Silpat-lined baking sheet. Bake for 8 minutes then quickly take the sheet out of the oven and bang it on the counter to encourage the cookie to spread and the marshmallow to explode out, then finish baking for another 2-4 minutes, the cookie dough should be just set, but not wet. Let cool on the baking sheet for five minutes before transferring it to a wire rack to cool completely. Store leftovers in an air-tight container for up to 5 days.
- Prep Time: 15 Minutes
- Chill Time: 30 Minutes
- Cook Time: 10 Minutes
- Category: Dessert
- Method: Bake
- Cuisine: American
Keywords: chocolate and marshmallow cookies, marshmallow stuffed chocolate cookies