Preheat oven to 500 degrees.
To make sauce, in a small saucepan set over medium heat, melt butter. Add minced garlic, stir and cook for 1 minute. Add flour, cook for 1 minute. Add milk and whisk continuously until a smooth. As the mixture thickens, season with salt, pepper and Italian seasoning. Simmer for 5 minutes, then reduce from heat and add the parmesan. Let cool for 15 minutes before using.
Roll out the dough into a 16" circle. Place on the pizza pan, then fold the overhanging dough over to form the crust. Press the edge to seal. Brush with olive oil, then bake for 5 minutes. Remove from the oven.
Spread the sauce over the pizza peel, then top with spinach, artichokes, mozzarella cheese and monterey jack cheese. Add the zucchini, yellow squash, red onion, diced tomato, green onion, oregano, red pepper, salt & pepper.
Bake for 10-12 minutes. Remove, and sprinkle with parmesan cheese, allow to cool for 8 minutes before slicing and serving.