I'm a huge fan of hot chocolate.

And I'm also a huge fan of this adorable mug cookie cutter from That's A Nice Cookie Cutter.

Because I'm CRAZIE about adding a 3D effect to most cookies, I added an extra thin layer of cookie dough to the marshmallow spots on these cookies.
Notice in the photo below that I used the top of the cutter to help make the marshmallow additions just the right size.

Outline and flood the mug portion of the cookie.
Add white glaze to form the marshmallows.

After some dry time, add the mug handles.
Outline the marshmallows to help them stand out even more.

Once the mug has dried for about 2 hours,
use an appropriate-sized cutter to imprint on the front of the mug.
Any Christmas-y shape will work well.

If desired, you can pipe detail elements around the impression to make it "pop".