What the heck is this?
Okay, so imagine if a Philly cheesesteak and a grilled cheese sandwich had a baby, and that baby grew up to be the most ridiculously indulgent casserole you’ve ever seen. That’s exactly what we’re dealing with here. We’re talking tender, seasoned beef, sautéed peppers and onions, and enough melted cheese to make a Philadelphian weep with joy — all layered between buttery, crispy bread that gets golden and crunchy on top while staying perfectly gooey underneath.
This is comfort food on steroids, people. It’s the kind of dish that makes you question why you ever bothered with actual sandwiches when you could just make this masterpiece instead. Fair warning: your kitchen is going to smell absolutely incredible, and you’re probably going to have people camping out at your dinner table begging for the recipe.
Why You’ll Love This Recipe
- Two iconic foods in one dish — it’s like winning the comfort food lottery
- Feeds a hungry crowd — perfect for game day or family gatherings
- Make-ahead friendly — assemble earlier, bake when ready
- Crispy AND gooey — hits all the texture notes
- Uses simple ingredients — no fancy stuff required
- Leftovers reheat beautifully — if there are any leftovers, that is
The Good Stuff You’ll Need
For the Philly Filling:
- 1.5 lbs thinly sliced ribeye or sirloin (ask your butcher to slice it thin)
- 2 large onions, sliced thin
- 2 bell peppers (mix of colors), sliced thin
- 8 oz mushrooms, sliced (optional but recommended)
- 3 cloves garlic, minced
- 2 tbsp olive oil
- 1 tbsp butter
- Salt and pepper to taste
- 1 tsp Worcestershire sauce
For the Bread Base:
- 8-10 slices thick-cut white bread (Texas toast style)
- 4 tbsp butter, melted
- 1 tsp garlic powder
For the Cheese Situation:
- 8 oz cream cheese, softened
- 1/2 cup mayonnaise
- 1 cup shredded provolone cheese
- 1 cup shredded American cheese (don’t judge, it melts like a dream)
- 1/2 cup shredded mozzarella
- 1/4 cup grated Parmesan
For the Egg Custard:
- 4 large eggs
- 1 cup whole milk
- 1/2 tsp salt
- 1/4 tsp black pepper
- 1/4 tsp smoked paprika
Let’s Do This
Step 1: Prep Your Baking Dish Preheat your oven to 350°F. Grease a 9×13 inch baking dish with butter or cooking spray. Set aside.
Step 2: Get That Bread Ready Cut your bread into 1-inch cubes. Toss with melted butter and garlic powder. Spread half the bread cubes in the bottom of your prepared baking dish.
Step 3: Cook the Philly Magic Heat olive oil and butter in a large skillet over medium-high heat. Add the sliced onions and cook for about 5 minutes until they start to soften. Add the bell peppers and mushrooms, cook another 5-7 minutes until everything is tender and slightly caramelized.
Push veggies to one side of the pan. Add the sliced beef to the empty side and cook for 2-3 minutes until just browned (it doesn’t need to be fully cooked since it’s going in the oven). Add garlic and Worcestershire, stir everything together, and season with salt and pepper. Remove from heat.
Step 4: Make the Cheese Sauce In a large bowl, mix the softened cream cheese and mayonnaise until smooth. Stir in the provolone, American cheese, mozzarella, and Parmesan until well combined.
Step 5: Whisk Up the Custard In another bowl, whisk together eggs, milk, salt, pepper, and smoked paprika until well combined.
Step 6: Layer Like a Boss Spread the beef and veggie mixture over the bread cubes in your baking dish. Drop spoonfuls of the cheese mixture all over the top (it doesn’t need to be perfect — rustic is the vibe here). Top with the remaining bread cubes.
Pour the egg mixture evenly over everything. Press down gently with a spatula to make sure the bread soaks up some of that liquid gold.
Step 7: Bake It ‘Til You Make It Cover with foil and bake for 30 minutes. Remove the foil and bake another 15-20 minutes until the top is golden brown and the center is set (a knife inserted in the center should come out mostly clean).
Step 8: Rest and Serve Let it rest for 10 minutes before serving — I know it’s torture, but this helps everything set up properly.
Serving Suggestions
- Serve with a simple arugula salad to cut through the richness
- A side of crispy fries because why not go full indulgence mode
- Pickles on the side for that classic Philly experience
- A cold beer or iced tea to wash it all down
Switch It Up
Chicken Cheesesteak Version: Use thinly sliced chicken thighs instead of beef Veggie Lover: Skip the meat and load up on more peppers, onions, and mushrooms Spicy Kick: Add sliced jalapeños or a dash of hot sauce to the beef mixture Different Bread: Try sourdough or even leftover hamburger buns Extra Cheesy: Because there’s no such thing as too much cheese, right?
Make-Ahead Tips
- Assemble the whole thing up to 24 hours ahead, cover and refrigerate
- The beef mixture can be cooked and stored for up to 3 days
- Prep all your veggies the day before to save time
- Leftover casserole keeps 4-5 days in the fridge and reheats beautifully
Questions People Actually Ask
Q: Can I use deli roast beef instead? A: Sure! Just chop it up and mix it with the sautéed veggies. It won’t be quite as tender, but it’ll still be delicious.
Q: What if I can’t find thin-sliced beef? A: Pop your beef in the freezer for 30 minutes, then slice it as thin as you can with a sharp knife. Or ask your butcher — they’re usually happy to help.
Q: Can I make this gluten-free? A: Absolutely! Just swap in your favorite gluten-free bread. The texture might be slightly different, but the flavor will still be on point.
Q: Is there a way to make this lighter? A: Use turkey or chicken instead of beef, swap half the cheese for reduced-fat versions, and use whole wheat bread. Still indulgent but a bit easier on the waistline.
Q: Can I freeze this? A: You can freeze the assembled (unbaked) casserole for up to 3 months. Thaw overnight in the fridge before baking, and add an extra 10-15 minutes to the baking time.
Print
Philly Cheesesteak Grilled Cheese Casserole
- Total Time: 1 minute
- Yield: 8–10 servings 1x
Description
Okay, so imagine if a Philly cheesesteak and a grilled cheese sandwich had a baby, and that baby grew up to be the most ridiculously indulgent casserole you’ve ever seen. That’s exactly what we’re dealing with here. We’re talking tender, seasoned beef, sautéed peppers and onions, and enough melted cheese to make a Philadelphian weep with joy — all layered between buttery, crispy bread that gets golden and crunchy on top while staying perfectly gooey underneath.
This is comfort food on steroids, people. It’s the kind of dish that makes you question why you ever bothered with actual sandwiches when you could just make this masterpiece instead. Fair warning: your kitchen is going to smell absolutely incredible, and you’re probably going to have people camping out at your dinner table begging for the recipe.
Ingredients
For the Philly Filling:
- 1.5 lbs thinly sliced ribeye or sirloin (ask your butcher to slice it thin)
- 2 large onions, sliced thin
- 2 bell peppers (mix of colors), sliced thin
- 8 oz mushrooms, sliced (optional but recommended)
- 3 cloves garlic, minced
- 2 tbsp olive oil
- 1 tbsp butter
- Salt and pepper to taste
- 1 tsp Worcestershire sauce
For the Bread Base:
- 8–10 slices thick-cut white bread (Texas toast style)
- 4 tbsp butter, melted
- 1 tsp garlic powder
For the Cheese Situation:
- 8 oz cream cheese, softened
- 1/2 cup mayonnaise
- 1 cup shredded provolone cheese
- 1 cup shredded American cheese (don’t judge, it melts like a dream)
- 1/2 cup shredded mozzarella
- 1/4 cup grated Parmesan
For the Egg Custard:
- 4 large eggs
- 1 cup whole milk
- 1/2 tsp salt
- 1/4 tsp black pepper
- 1/4 tsp smoked paprika
Instructions
Step 1: Prep Your Baking Dish Preheat your oven to 350°F. Grease a 9×13 inch baking dish with butter or cooking spray. Set aside.
Step 2: Get That Bread Ready Cut your bread into 1-inch cubes. Toss with melted butter and garlic powder. Spread half the bread cubes in the bottom of your prepared baking dish.
Step 3: Cook the Philly Magic Heat olive oil and butter in a large skillet over medium-high heat. Add the sliced onions and cook for about 5 minutes until they start to soften. Add the bell peppers and mushrooms, cook another 5-7 minutes until everything is tender and slightly caramelized.
Push veggies to one side of the pan. Add the sliced beef to the empty side and cook for 2-3 minutes until just browned (it doesn’t need to be fully cooked since it’s going in the oven). Add garlic and Worcestershire, stir everything together, and season with salt and pepper. Remove from heat.
Step 4: Make the Cheese Sauce In a large bowl, mix the softened cream cheese and mayonnaise until smooth. Stir in the provolone, American cheese, mozzarella, and Parmesan until well combined.
Step 5: Whisk Up the Custard In another bowl, whisk together eggs, milk, salt, pepper, and smoked paprika until well combined.
Step 6: Layer Like a Boss Spread the beef and veggie mixture over the bread cubes in your baking dish. Drop spoonfuls of the cheese mixture all over the top (it doesn’t need to be perfect — rustic is the vibe here). Top with the remaining bread cubes.
Pour the egg mixture evenly over everything. Press down gently with a spatula to make sure the bread soaks up some of that liquid gold.
Step 7: Bake It ‘Til You Make It Cover with foil and bake for 30 minutes. Remove the foil and bake another 15-20 minutes until the top is golden brown and the center is set (a knife inserted in the center should come out mostly clean).
Step 8: Rest and Serve Let it rest for 10 minutes before serving — I know it’s torture, but this helps everything set up properly.
Notes
- Serve with a simple arugula salad to cut through the richness
- A side of crispy fries because why not go full indulgence mode
- Pickles on the side for that classic Philly experience
- A cold beer or iced tea to wash it all down
- Prep Time: 30 minutes
- Cook Time: 45-50 minutes
Nutrition
- Calories: ~520 kcal
- Carbohydrates: ~32g
- Protein: ~28g