The solution: Sear the crust first to firm it up. Put your pan or pizza stone in the oven as it preheats, and arrange the dough on the hot pan before you top; this sets the crust. For veggie pizzas, sauté toppings to keep ingredients like zucchini and mushrooms from watering out as they bake, and use restraint with those toppings. Spread a scant layer of sauce (about ¼ cup), so the dough is still visible underneath, and finely chop or thinly slice vegetables (big chunks cook unevenly). If you have very fresh mozzarella, drain off any excess milk before adding.