Preheat the oven to 375°F. Place the baking stone on the bottom rack to preheat with the oven. If you don't have a baking stone, place a baking sheet on the bottom rack instead.
On a separate baking sheet, sprinkle the cornmeal. Place the rolled out round of pizza dough on top of the cornmeal.
Brush a thin layer of olive oil onto the crust. Brush minced garlic onto the crust too. Sprinkle lightly with garlic salt. Sprinkle ½ cup of the mozzarella cheese as the first layer. Sprinkle fresh spinach on top of the cheese. Then add the mushrooms, onion and tomato. Top with the remaining mozzarella and feta cheese. Sprinkle basil on top.
Slide the pizza onto the hot stone and bake until the crust is browned and the cheese is bubbly. Set the timer for 8 minutes, then check and add more time, if needed. When done, remove the pizza from the oven by sliding the baked pizza onto a large cutting board. Use a pizza cutter to cut into 6 slices.
Notes
*Play with the veggies on this one... add or substitute your favorites.