-
Preheat oven to 350 and line a baking sheet with parchment paper.
-
With a mixer, beat butter and sugar until light and fluffy. Add in the egg and vanilla. Beat.
-
Once mixed, in a small bowl, sift cocoa powder, flour, espresso powder, baking soda, baking powder, and salt together. Slowly add dry ingredients into the wet. Mix until combined.
-
Add in milk and mix until combined. The dough will be thick.***
-
Roll dough into 1-2 Tbsp sized balls (depending upon how big of cookies you want). Once on the cookie sheet, press your thumb into the center of the cookie (the edges will crack slightly).
-
Bake cookies for 8 minutes.
-
Pull cookies out and press marshmallows in the thumbprint-centers. Bake for 2-3 more minutes, or until cookies are done and marshmallows have begun to puff up.
-
While the cookies are cooling, with a double broiler (or microwave), melt chocolate chips and vegetable oil together.
-
Once melted, spoon a little bit onto each cookie. If you want to add any chocolate drizzles, put some chocolate in either a piping bag or a small sandwich bag with the tip cut off and drizzle over cookies.
-
Add toppings to your liking. Allow chocolate to set, about 30-60 minutes at room temperature.
-
Enjoy with milk!