1. Preheat oven to 425°F.
2. In a small bowl, mix milk and apple cider vinegar together and set aside.
3. In a large bowl, add flour blend ingredients and whisk together.  I recommend using a digital scale to measure the flour instead of using the cup measurements to make sure the correct amount of flour is used.
4. Set a piece of parchment paper onto the counter, measure 1/2 cup of the flour mixture, and place onto of the parchment paper.
5. Add baking powder, baking soda, xanthan gum, and salt to the large bowl of flour and whisk together.
6. Add 2 tbsp of melted butter to the milk and apple cider vinegar mixture.
7. Pour the milk mixture into the dry ingredients and stir until a sticky dough forms.
8. Transfer dough to the floured parchment paper and knead the remaining flour into the dough. Divide the dough in half.
9. Using your hands and a rolling pin, press and roll the dough into a 10″ circle. Do the same thing for the second half of dough.
10. Transfer the rolled dough to pizza pans or pizza stones for best results.
11. Spread the remaining 2 tbsp of butter onto the two pizzas and bake in the oven for 12 minutes.
12. While the pizza crust is baking, saute onion and mushrooms in 2 tbsp of olive oil for 5-7 minutes until soft.
13. Take the pizza out of the oven and add your toppings. Bake for an additional 5-8 minutes until the crust has slightly browned on the bottom and is crispy.

To Freeze and Cook Later

1. Prepare dough according to the directions above (steps 2-11).
2. Take the pizza out of the oven and add your toppings.
3. Once the pizza has cooled, wrap the whole thing in plastic wrap and then cover the plastic wrap in aluminum foil. Freeze for up to to three months.
4. When ready to cook, bake for an additional 5-8 minutes at 425°F until the crust has slightly browned on the bottom and is crispy.