1.
Preheat grill with grill basket to medium heat.
2.
Toss mushrooms, zucchini, bell peppers, and onion with vinegar, water, and oil. Season with basil, salt, and pepper.
3.
Pour vegetables into grill basket and close grill lid. Cook for about 10 minutes, stirring midway through cooking time, until vegetables are cooked through and softened.
4.
Preheat oven to 450 degrees F.
5.
Spread prebaked pizza crust with pizza sauce, then pour the vegetables on top and spread into an even layer. Add sliced tomatoes and shredded cheese.
6.
Bake for about 15 minutes, until pizza is heated through and cheese is bubbling.