Pizza is always a crowd-pleaser, and the cheese-filled crust of our veggie pie makes it all the more appetizing. The bulked-up edge allows you to pile the filling high, deep-dish style.
First, make the dough. Pour the water into a large mixing bowl and sprinkle in the yeast. Stir in the sugar and oats, then set the mixture aside for 5 minutes. Stir in the oil and salt. Add 2 cups of the flour and beat the mixture with a wooden spoon for 100 strokes. Set the mixture aside for 5 minutes more.
Add the remaining flour, L cup at a time, and beat well after each addition. When the dough is firm and pliable, place it on a floured surface and knead it until it's smooth and somewhat springy, about 8 minutes. If the dough becomes sticky, add more flour as you knead.
Place the dough in a large, lightly oiled bowl and turn the dough to coat it with the oil. Cover the bowl with plastic wrap and set it aside in a warm spot until the dough has doubled in bulk, about 1 hour.
While the dough rises, prepare the topping. In a large skillet over medium heat, warm 2 tablespoons of the olive oil. Add the onion and bell pepper and sauté them, stirring often, until they are soft, about 4 minutes. Stir in the garlic and sauté for 1 minute more. Transfer the mixture to a plate.
In the same skillet over medium heat, warm the remaining olive oil. Add the mushrooms and broccoli and lightly sauté the vegetables for 4 minutes (they should still be crunchy). Transfer them to the plate with the other vegetables.
Heat the oven to 425º. Oil a large cookie sheet, dust it with the cornmeal, then set it aside. Punch down the dough and turn it out onto a lightly floured surface. Knead it briefly, then let it rest for 5 minutes.
Roll out the dough so that it's 1/4-inch thick and the size of the cookie sheet. Place it on the sheet. Sprinkle half of the mozzarella along the perimeter of the dough, about 1 inch in from the edges. Moisten the edges, fold them over the cheese, and press to seal them in place.
Spread the tomato sauce over the pie. Add the cooked vegetables and diced tomato. Lightly salt and pepper the vegetables and sprinkle on the rest of the cheese. Bake the pie on the center rack until the crust is golden brown, about 25 minutes.
Remove the pie from the oven and brush the crust with more olive oil. Slide the pie onto a cooling rack and allow it to cool briefly before serving. Makes 8 slices.
Per serving (one slice): Calories 443 • Total Fat 16 g • Saturated Fat 8 g • Cholesterol 30 mg • Sodium 1,107 mg