Preheat oven to 350 degrees F. Oil muffin tin and set aside.
Cook onion and peppers in an oiled skillet over medium-high heat until onions are translucent and vegetables are tender. Remove from heat.
Whisk together sorghum flour, potato or corn starch, tapioca starch, baking powder, Italian seasoning, xanthan or guar gum, salt, and black pepper in mixing bowl.
Mix together eggs, pizza sauce, olive oil and milk substitute and add to dry ingredients. Mix together until well blended.
Fold in onions and peppers, cooked sausage, pepperoni, black and green olives and ½ cup of the shredded cheese substitute into batter. Divide batter in a 12-muffin muffin tin.
Bake in preheated 350 degree F oven for 25 minutes or until they test done with a toothpick. Turn off oven. Dividing between muffins, top muffins with remaining shredded cheese, if using. Put back in warm oven for 2 minutes until cheese substitute is melted. Remove from oven and place muffins onto cooling rack after taking out of baking tin.
To freeze: Allow to completely cool, then place muffins in a freezer safe container or freezer bag. Remove as much air as possible, seal, label, and freeze.
To serve: Thaw. Eat at room temperature or warm through.