With a mixer, cream butter until light and fluffy, about 1 minute. Add in brown sugar and white sugar and mix until well combined.

Add in the egg and vanilla extract. Mix.

In a separate bowl, sift together flour, cocoa powder, baking soda, cornstarch, salt, and espresso powder. Once combined, slowly incorporate dry ingredients into wet ingredients. Mix until just combined.

Add in M&Ms, almonds, and semi-sweet chocolate chips. Mix. Once combined, chill dough in refrigerator for about 20 minutes (this makes the dough easier to work with).

Preheat the oven to 350 degrees. Line a baking sheet with parchment paper or spray with cooking oil.

Take about 2 Tbsp of dough and flatten it slightly in your hand. Stick 3-4 marshmallows in the center, and fold the cookie dough around the marshmallows and form it into a ball. Make sure none of the marshmallows can be seen in the dough.

Place on cookie sheets, about 2 inches apart.

Bake for 13-15 minutes, or until the cookies are done.

Enjoy!