Preheat oven to 400 degrees, sprinkle a round pizza pan with a light layer of corn meal.
While oven preheats, add 1 tbsp extra virgin olive oil to large sauté pan along with sliced onions, toss to coat and cook over medium-low heat, stirring frequently for 15-20 minutes or until onions become soft and caramelized. Remove from the pan and set aside.
While onions cook, roll the dough out according to package’s directions. I found that rolling it out on a clean, hard surface with corn meal worked best for me. Prebake pizza for 10 minutes. Remove and set aside.
In the same skillet as you cooked the onions (don’t clean), add additional tbsp extra virgin olive oil, followed by minced garlic cloves, cook 1-2 minutes, stirring frequently until fragrant.
Add baby belly mushrooms and stir until coated in olive oil and garlic. Add 1 tbsp water, followed by dried thyme, basil, salt and pepper. Stir until seasonings are well mixed, then cook 5-6 minutes, stirring occasionally, until mushrooms are tender and browned.
Add thawed shrimp (tails removed) to the mushrooms, then stir and cook 2-3 minutes. Remove mushrooms and shrimp from pan, leaving as much of the “juice” in the pan as possible, then set aside.
In a small bowl, mix 1 tbsp water with 1 tsp corn starch, add mixture to hot pan with left over seasoning/juice, along with 1/4 cup 2% milk, garlic salt and pepper. Bring to a low boil, then reduce heat and allow to simmer for 3-4 minutes or until thick. This does not make a large amount of sauce (see picture), but you just need enough for a light coating over the pizza.
Top prebaked Gluten-Free pizza dough with sauce, followed by baby spinach leaves, mozzarella cheese, caramelized onions, mushrooms and shrimp. Finally, add shaved Parmesan cheese, and bake additional 5-6 minutes or until cheese is melted and pizza is warmed through.
Garnish with fresh parsley, additional shaved parmesan and crushed red pepper if desired. Serve immediately and enjoy!