Preheat the oven to 350°F. Spray a 1 1/2 quart baking dish with cooking spray, set aside.
In a medium size saucepan, heat a few drizzles of olive oil. Add the sliced steak. Cook for for 2-3 minutes until browned or to your desired doneness. Season lightly with Montreal steak seasoning. Remove from the pan.
Add the diced onion, green bell pepper and sliced mushrooms to the pan. Season with seasoned salt and black pepper. Add additional olive oil, if needed. Cook for 5-7 minutes until browned and the liquid from the mushrooms has evaporated. Drain any excess fat from the pan.
Lower the heat and add the cubed white American cheese, 1/2 cup cream, cream cheese, steak seasoning, dry Italian seasoning and granulated garlic. Cook until the American cheese and cream cheese has completely melted. Add additional half & half as needed to thin.
Remove from the heat and add the steak to the melted cheese. Mix until combined.
Pour the dip into the baking dish and top with shredded mozzarella cheese. Bake for 20-25 minutes until golden and bubbly.
Serve with pita chips or garlic bread for dipping.
Add 1/2 cup of cream to melt the cheese. After adding the remaining ingredients you may thin the dip with additional cream if desired.