Preheat oven to 450°F (convection 400°F).
Sauté peppers and onion in vegetable oil, just until soft. Set aside.
Prepare biscuit mix according to package directions, using the milk.
For 16-inch pizzas, divide dough into 5 equal pieces.
On a well-floured surface, roll dough pieces until 16 inches in diameter (around ⅛ inch thick). Using a docker, run over the dough in multiple directions, until dough is well docked.
Carefully transfer dough to pizza pan.
Ladle 18 oz. of gravy to middle of dough, within ¾ inch of the outside edge. Top with 8 oz. of sautéed onion/pepper mixture and then 8 oz. of cheese.
Bake for 10-12 minutes (8-11 convection). Brush outside edge of pizza with melted butter upon removal from oven.