In a small saucepan, heat 1 tbsp olive oil over medium heat. Add minced garlic and cook for 30 seconds until fragrant. Stir in crushed tomatoes, dried oregano, dried basil, salt, pepper, and sugar (if using). Bring to a simmer, then reduce heat to low and cook for 5-7 minutes, stirring occasionally, until slightly thickened. Remove from heat and set aside.

While the sauce simmers, preheat your oven to 450°F (230°C). In a large mixing bowl, combine the sliced red bell pepper, green bell pepper, red onion, mushrooms, zucchini, and halved cherry tomatoes. Drizzle with 1 tbsp olive oil, sprinkle with 1/4 tsp salt and 1/8 tsp black pepper, and toss gently to coat evenly. This light seasoning enhances their flavor.

Lightly grease a 13x18 inch baking sheet with 1 tbsp olive oil. Place the room temperature pizza dough in the center of the baking sheet. Using your fingertips, gently stretch and press the dough out to cover the entire baking sheet, forming a rectangular crust. If the dough springs back, let it rest for 5 minutes and then continue stretching.

Evenly spread the prepared tomato sauce over the pizza dough, leaving about a 1/2-inch border for the crust. Sprinkle 1.5 cups of the shredded mozzarella cheese over the sauce, followed by the grated Parmesan cheese. Distribute the seasoned vegetables evenly over the cheese. Top with the remaining 1/2 cup of shredded mozzarella.

Carefully transfer the baking sheet to the preheated oven. Bake for 20-25 minutes, or until the crust is golden brown and crispy, the cheese is melted and bubbly, and the vegetables are tender-crisp.

Once out of the oven, immediately scatter the fresh spinach over the hot pizza; the residual heat will gently wilt it. Let the pizza rest on the baking sheet for 5 minutes before slicing into squares. Garnish with fresh chopped basil and red pepper flakes, if desired, before serving.