Ingredients
Vegetables
- 1 large green bell pepper
- 1 large yellow bell pepper
- 1 large red bell pepper
- 1 small onion, thinly sliced (about ½ cup)
- 8 ounces cremini mushrooms, thinly sliced
- 3 cloves garlic, minced
Dairy & Butter
- 2 tablespoons salted butter
- 6 slices provolone cheese (about 6 ounces)
- 1 cup shredded mozzarella cheese
Meat
- 1 ½ pounds deli-style roast beef, thinly sliced
Instructions
- Prepare the peppers: Cut the tops off the green, yellow, and red bell peppers, remove the ribs and seeds, then thinly slice the peppers. Set them aside for later use.
- Sauté onions and garlic: Heat 2 tablespoons of salted butter in a large deep-sided ovenproof skillet or Dutch oven over medium-low heat. Add the thinly sliced onion and minced garlic and cook until the onion becomes translucent and the garlic is fragrant, about 7 minutes.
- Cook mushrooms and peppers: Add the thinly sliced cremini mushrooms and the prepared bell peppers to the skillet. Continue cooking until the mushrooms release their liquid and the peppers become crisp-tender, approximately 10 minutes.
- Preheat oven: While the vegetables are cooking, preheat your oven to 350°F (175°C) to prepare for baking the casserole.
- Add roast beef and combine: Add the 1 ½ pounds of thinly sliced deli-style roast beef to the skillet with the cooked vegetables. Stir to evenly combine. Taste the mixture and season with salt and pepper as desired.
- Add cheese toppings: Lay the 6 slices of provolone cheese evenly over the beef and vegetable mixture. Then sprinkle 1 cup of shredded mozzarella cheese evenly over the top to create a melty, cheesy crust.
- Bake the casserole: Place the skillet in the preheated oven and bake uncovered for 15 minutes to melt the cheese and heat everything through.
- Broil for finish: After baking, switch your oven to the broiler setting and broil the casserole for 2 to 3 minutes, or until the cheese is browned and bubbly, keeping a close eye to prevent burning.
Notes
- You can use a large ovenproof skillet or a Dutch oven to cook and bake the casserole all in one pan, reducing cleanup.
- Adjust seasoning with salt and pepper after adding the roast beef to suit your taste.
- If you prefer, substitute provolone and mozzarella with other melty cheeses like fontina or Monterey Jack.
- Make sure to watch the casserole closely during broiling to avoid burning the cheese.
- This casserole is naturally gluten free as it contains no bread or gluten ingredients.
- Leftovers can be refrigerated for 3-4 days and reheated in the oven or microwave.
- Prep Time: 15 minutes
- Cook Time: 30 minutes
- Category: Main Dish
- Method: Baking
- Cuisine: American
- Diet: Gluten Free
