Spread pizza sauce over dough, leaving a 1/2-inch border; top evenly with spinach. Sprinkle mozzarella over spinach. Arrange eggplant, zucchini, and squash slices alternately over cheese. Top evenly with onion and bell pepper mixture.

By skipping the sodium-laden meats, we pack a full serving of vegetables into each square, thereby doubling the fiber of most pizza chain offerings. Still every bit as satisfying as its meaty counterparts, our pie will delight even the most devout of carnivores. The dough develops a focaccia-like texture from a 24-hour resting period in the refrigerator.