Using a stand mixer, cream butter, sugars and vanilla together.

Add in egg and combine

In a separate bowl, combine flour, corn starch, baking powder, salt and hot chocolate

Slowly add the flour mixture into the wet ingredients

Note: Dough will be very thick. You may need to finish combining the ingredients by hand if your mixer cannot handle the thickness of the dough

Add in chocolate chips and combine

Chill the dough for a full hour

Preheat oven to 350 F

Scoop a small amount of dough into your hands and roll into a ball. Create a "nest" in the center of each ball of dough and place on a greased cookie sheet

Add a few marshmallows into each nest

Flatten a small piece of dough with your hands big enough to cover the nest, and gently press each cookie down to flatten it a little

Bake for 12 minutes, or until the edges are golden brown

Note: The cookies will still look very soft when you take them out of the oven. That's normal - they will continue to cook as they are cooling

Serve with a glass of hot chocolate and enjoy!

Yields 1 dozen