Roast Hard Veggies: Preheat oven to 450°F (232°C). Place your pizza pan in the oven to heat up as well. Halve eggplant and zucchini lengthwise then slice into ¼ inch pieces. Spread onto a baking sheet and drizzle with 1 Tbsp of oil. Roast for about 15 minutes, or until slightly tender. Do no turn off oven when veggies have finished.
Saute Soft Veggie: Meanwhile, slice onion and peppers. Add to a saute pan with 1 Tbsp of oil and cook over medium/high until slightly soft, about 5 minutes. Remove from pan and add spinach. Cook until completely wilted down, about 3 minutes.
Assemble: Roll out pizza dough onto parchment paper, lightly brushing the top with remaining oil. Spread on tomato sauce, sprinkle with cheese, then top with all your veggies. Slide the parchment paper and pizza onto your preheated pizza pan, then bake for 15 minutes, or until crust is golden brown. Serve warm with salt and/or pepper flakes as needed.