In a medium sauce pan, melt butter and 12 oz. of chocolate together until the chocolate has melted. It’s easiest to chop up your chocolate into smaller chunks to make the melting process quicker.
Take the pan off the heat and let it cool for 15 minutes.
Mix sugar, eggs, and vanilla together with an electric mixer until blended.
In another bowl, whisk flour, xanthan gum (if using), cocoa powder, baking powder, and salt together into incorporated.
After the butter and chocolate mixture has fully cooled to room temperature, add it to the egg/sugar mixture and give it a few stirs until just blended.
Next add your flour mixture to the wet mixture and blend with the electric mixture. I find it’s always better to add the flour in two parts to make sure it all gets blended and so I don’t make a total mess of the kitchen. At this point, the dough should have a relatively thick consistency.
Next, you will want to refrigerate the dough for an hour or so until the dough is easy to roll into balls.Preheat the oven to 325 degrees and take out your cookies sheets.
After the dough has hardened a bit, roll the dough into 1 inch balls and place 2 inches from one another. We were able to get 15 dough balls onto each cookie sheet.
You’ll bake the cookies for about 10 minutes or until the cookies start to crack. When this happens, take the cookies out and place your chocolate chunks onto the center of the cookies and place a halved marshmallow on top of the chocolate chunk.
Next, put the cookies back in the oven for about 4 minutes or until the marshmallow has melted/softened. Now, grab that hot cocoa or eggnog I mentioned above and enjoy your gooey hot cocoa cookies!