Combine the coconut flour, cocoa powder, allulose, baking powder, Salt and Cinnamon in a 12 oz mug and mix with a fork or small whisk to break up any clumps.
Add the half and half, egg, and vanilla to the dry ingredients and mix to combine, making sure no dry ingredients are hiding at the bottom.
Sprinkle the chocolate chips evenly over the cake batter (if you mix them in they tend to sink to the bottom).
Microwave for 90 seconds. If your microwave is under 1000 watts, you may need to cook it longer. No microwave? Mix the cake in an oven-safe dish like a ramekin and bake at 350 degrees F for approximately 15 minutes.