Preheat the oven to 350 degrees F.
In a skillet, cook onion, bell pepper, and mushroom for 10 minutes. You should cook on medium heat and let the ingredients sauté.
Add garlic and cook for further 3 minutes.
Now in a bowl, add the salt, pepper, cheese whiz, sauce, ketchup, eggs, breadcrumbs, and the cooked mixture.
Mix it well and add half of the prepared meat to the bottom of the baking dish. Add the provolone solid cheese in the middle and the remaining meat on top. Seal the edges with the help of your fingers.
Bake it for 60 minutes and then add the slices of cheese on top. Bake it for 5 minutes and your delicious meal is ready to serve.