Pre-heat oven to 350*F.
In a small bowl, whisk together your almond flour, sweetener, baking powder, xanthan gum and salt. Set aside.
In another microwavable bowl, melt your mozzarella in 30s increments until you can easily stir it (it took about 1 min for me in total).
Add your already whisked egg and your dry ingredients to the melted mozzarella and stir very well until a dough starts to form. At first the mozzarella may not completely stick to the other ingredients. This is okay, just begin to knead the dough like you would bread dough until the mozzarella is incorporated.
If the mozzarella still doesn’t want to blend into the other ingredients after a minute or two of kneading, place everything back in the microwave for 10-15s and then knead the dough again. Repeat this as needed until all ingredients are incorporated well and you can form a nice clean ball.
Roll out your ball of dough between two sheets of greased parchment paper about an inch thick.
Use a glass to make circular cut-outs. Re-roll out the scraps until all of the dough is gone.
Place the parchment paper with the cut-outs on it on top of a cookie sheet and bake them for 25-30min (these won't brown a lot but you can tell by touch when they are about done).
After they have cooled, gently slice each donut in half with a sharp knife like you would a bun and use a spoon to place an even amount of pastry cream in the center of one of the halves. Top it off with the second piece like a sandwich and repeat this for the rest of the donuts.
To make the glaze, simply heat your heavy cream in a microwavable measuring cup for 1min then pour over the chocolate chips to melt them. Also add the vanilla extract at this time. Stir until smooth. (Pop the bowl in a microwave for 10-15s if the chocolate chips are not completely melted).
Spoon some of the glaze over the top of a donut and use the back side of the spoon to spread it out in a circular motion. Repeat for the remaining donuts. Finished! Enjoy your Keto Boston Cream Donuts!