Preheat oven to 450 degrees.

Grease a 13x9x2 inch rectangular baking dish.

Cook Italian sausage and ground beef in a skillet over medium heat, stirring until brown.

Drain excess fat from the meat mixture.

Set the cooked meat aside.

In a large bowl, stir together Bisquick and cold water until a dough forms.

Divide the dough into two parts, one slightly larger than the other.

On a surface dusted with Bisquick, roll the larger dough portion into a 16x14 inch rectangle.

Fold the dough crosswise into thirds.

Place the folded dough in the center of the prepared baking dish and unfold it.

Press the dough onto the bottom and up the sides of the dish.

Sprinkle 1 cup of mozzarella cheese over the dough in the dish.

Top with 3/4 cup of pizza sauce, the cooked meat mixture, sliced mushrooms, and chopped green bell pepper.

Sprinkle 1 1/2 cups of mozzarella cheese over the toppings.

Roll the remaining dough portion into a 13x9 inch rectangle.

Fold the dough crosswise into thirds.

Place the folded dough on top of the cheese and toppings in the baking dish and unfold it.

Press the bottom and top crust edges together to seal.

Make small slits in the top crust to vent steam.

Spread the remaining pizza sauce over the top crust.

Sprinkle the remaining mozzarella cheese over the sauce.

Bake uncovered for 22 to 25 minutes, or until the edges of the crust are golden brown.