Preheat oven to 350°F and spray a donut pan with non-stick spray.

Combine the milk and vinegar together in a liquid measuring cup and set aside.

In a large bowl, sift together the flour, xanthan gum, sugar, baking powder, baking soda and salt. Stir well to combine and mix in the chocolate chips.

In a separate bowl, whisk together the egg, oil, vanilla and milk/vinegar mixture. Add the wet ingredients to the dry ingredients and mix well.

Pour the batter into a large ziplock bag. Cut a small section of the bottom corner off and use the bag to pipe the batter into the prepared donut pan. If you only have one pan, you’ll have to bake the donuts in two batches.

Bake the donuts for 8-10 minutes. The donut will spring back when done.

Cool the donuts on a wire rack. If you need to bake a second batch, wipe the donut pan and re-spray with non-stick spray between batches.

Add 1/2 cup chocolate chips, butter, corn syrup and water to a microwave safe bowl and heat at 50% power for for 60 seconds. Stir well and continue to heat at 50% power for 20 second intervals (stirring each time) until the chocolate is melted.

Dip the donuts in the glaze and then top with extra mini chocolate chips if using. Store leftovers in an airtight container.