Heat the olive oil in a skillet over medium heat. Brown the ground beef with the onion, stirring frequently, until the beef is no longer pink. Remove from the heat and set aside.
In a bowl, combine the flour, salt, pepper, and basil.
In a small bowl, whisk the eggs with the milk. Pour into the flour mixture and stir until well blended. Pour the mixture into the prepared baking pan and spread lightly to cover the bottom.
Sprinkle the ground beef mixture evenly over the batter layer.
Bake for 20 minutes. Remove from the oven.
Spread with the pizza sauce and then top with the pepperoni, mushrooms, olives, and bell pepper, if using. Or, top with your favorite toppings.
Sprinkle evenly with the shredded cheese.
Bake the pizza for 15 minutes longer, or until the toppings are hot and the cheese has melted.