Preheat oven to 375 degrees.
Line a sheet pan with parchment paper.
Cook cauliflower rice two minutes in the microwave. Stir.
Microwave two more minutes.
Transfer cauliflower rice to a dish towel and squeeze out water until mostly dry.
Transfer to the bowl of a food processor.
Add eggs, garlic powder and lime juice.
Process until incorporated.
Add the parsley, salt, pepper, 3/4 cup shredded mozzarella, xanthum gum, garlic powder and Carbquik.
Divide the mixture evenly on the baking sheet.
Flatten with the back of a spoon.
Bake 10 minutes.
Flip and bake 6-7 more minutes.
Remove and place on a baking rack to cool about 10-15 minutes.
Heat some extra virgin olive oil in a skillet.
Brown each tortilla until the surface is browned. Remove and set aside.
In the same skillet, heat the butter.
Saute the sliced onions for about 20 minutes. They should be a nice caramel-brown color.
Remove the onions and set aside
In the same skillet, heat some more butter.
Saute the mushrooms, garlic, parsley, salt and pepper until softened.
Place the cauliflower flatbreads back on the baking sheet.
Spread some pesto or alfredo sauce on the flatbreads.
Top with onions, mushrooms and cheese.
Bake until the cheese is melted and the flatbreads are heated through.