1. From focaccia mix, combine flour packet, seasoning packet, yeast packet and cheese packet in bowl. Add warm water, 1 tablespoon oil and 2 tablespoons flour; stir to blend.
2. Sprinkle remaining flour on work surface. Turn dough out on surface; knead lightly. Spread, stretch onto greased, perforated 12-inch round pizza pan. Press dough to edges, forming small rim. Cover with clean towel. Let rise 20 minutes.
3. Place oven rack in lowest position. Heat oven to 425 degrees F.
4. Heat remaining 2 tablespoons oil in large skillet. Add peppers, onion; saute 5 minutes. Add mushrooms, garlic, 1/2 teaspoon salt, the pepper; cook 3 minutes, until mushrooms release liquid. Remove from heat.
5. Spread crust with pizza sauce, leaving 1/2-inch border. Top with veggies, cheese and remaining salt.
6. Bake in 425 degrees F oven 20 minutes, until browned around edge, cheese melted. Let cool 5 minutes. Makes 8 servings.