Preheat oven to 425°F (220°C).

Lightly grease a jelly roll pan.

In a mixing bowl, combine Bisquick mix and water until a soft dough forms.

Pat the dough evenly into the bottom and up the sides of the prepared jelly roll pan.

In a skillet over medium heat, cook ground beef, chopped onions, crushed garlic, and sliced green pepper until the beef is browned.

Drain off any excess grease.

In a separate bowl, mix tomato sauce and Italian seasoning.

Spread the tomato sauce mixture evenly over the dough.

Spoon the cooked beef mixture over the sauce.

Top with sliced mushrooms and shredded Mozzarella cheese.

Bake in the preheated oven until the crust is golden brown and the cheese is melted and bubbly, about 20 minutes.