A Sub in a Tub is the ultimate crowd-pleasing party dish that combines all the delicious elements of a classic submarine sandwich layered together in one irresistible casserole. This is the kind of recipe that feels fancy enough for entertaining but comes together with such ease that you’ll find yourself making it again and again. Think of it as deconstructed sub sandwich heaven—all those wonderful Italian flavors, creamy mayo, fresh vegetables, and perfectly seasoned meats combined in a way that’s actually easier to serve than traditional subs.
I absolutely love making this dish because it’s so versatile and forgiving. Whether you’re feeding a family of four or hosting a casual get-together, you can easily adjust the portions and ingredients to suit your needs. The beauty of this recipe lies in its simplicity and the way all the flavors meld together as it bakes. The bread becomes wonderfully soft and absorbs all the delicious juices from the filling, while the cheese on top gets melty and golden.
The magic of Sub in a Tub really comes down to quality ingredients and proper layering. You want to start with a good Italian bread base, then layer your favorite sub sandwich fillings, and top it all with melted cheese. Some people like to add a splash of Italian dressing for extra flavor, and I’m absolutely here for that decision. The result is a dish that tastes like your favorite sub sandwich but with a texture that’s more like a savory bread pudding.
What I love most about this recipe is how it brings people together. There’s something so satisfying about serving a big bubbling casserole straight from the oven. Your guests will be asking for seconds, and honestly, the leftovers are just as delicious the next day. You can serve this alongside pizza sides or fresh salad for a complete meal.
I’ve also found that this dish is perfect for meal prep because you can assemble it the night before and just pop it in the oven when you’re ready to eat. This makes it ideal for busy weeknights when you want something special without spending hours in the kitchen. The recipe is also very customizable—use your favorite deli meats, add extra vegetables, or adjust the cheese based on your preferences.
For the absolute best results, I recommend using quality deli meats from the counter rather than pre-packaged options. The difference in flavor is noticeable, and your dish will taste noticeably better. Similarly, freshly grated cheese melts more smoothly than pre-shredded varieties. These small touches elevate the entire dish and make it taste homemade in the best possible way.
One of my favorite variations is to add some roasted red peppers or fresh tomatoes to the layers. You can also experiment with different cheese combinations—provolone, mozzarella, and a little sharp cheddar create a wonderful flavor profile. Some people love adding pepperoni for extra richness, and I think that’s a brilliant addition.
The timing of this dish is also wonderfully flexible. You can make it in the morning, refrigerate it, and bake it for dinner. Or assemble it just before baking for a quicker weeknight meal. Either way, you’re going to end up with something absolutely delicious that feels like a special occasion dinner but requires minimal effort.
I genuinely believe that this Sub in a Tub recipe deserves a permanent spot in your rotation. It’s the kind of dish that works for casual family dinners, potlucks, game day gatherings, or even Sunday suppers. The combination of flavors is timeless, and the execution is foolproof. Once you master the basic technique, you’ll find yourself making it regularly and adapting it based on what you have on hand.
If you’re looking for other crowd-pleasing dishes to round out your menu, consider pairing this with butter swim biscuits for a truly indulgent meal. Or serve alongside tasty breadsticks for extra bread options. A fresh pineapple coleslaw provides a nice contrast to the rich, savory casserole. And don’t overlook the option to serve with a bowl of white queso dip for dipping pieces of the casserole.
I’ve made this recipe countless times, and it never disappoints. The feedback I get is always the same: people are amazed at how simple it is to make and how incredibly delicious it tastes. That’s really the hallmark of a great recipe—something that looks fancy but comes together easily, tastes absolutely wonderful, and makes everyone happy. This Sub in a Tub definitely checks all those boxes.
Ingredients
- 1 large loaf Italian bread, sliced in half lengthwise
- 1 cup mayonnaise
- 2 tablespoons Italian seasoning
- 1 tablespoon garlic powder
- 1 tablespoon onion powder
- 1 pound sliced deli roast beef
- 1 pound sliced deli turkey
- 8 ounces sliced provolone cheese
- 8 ounces sliced mozzarella cheese
- 1 large red bell pepper, thinly sliced
- 1 large green bell pepper, thinly sliced
- 1 red onion, thinly sliced
- 8 ounces sliced tomatoes
- 1 cup sliced black olives
- 1 cup roasted red peppers
- 1/2 cup Italian dressing
- 4 ounces sliced pepperoni (optional)
- Salt and pepper to taste
- Fresh basil for garnish (optional)
Instructions
- Preheat your oven to 350 degrees Fahrenheit. Line a 9×13 inch baking dish with foil or parchment paper for easy cleanup, or lightly grease it with cooking spray.
- Place both halves of the Italian bread in your prepared baking dish, cut side up. If the bread is too long, you can trim it to fit or arrange it in an overlapping pattern.
- In a small bowl, combine the mayonnaise, Italian seasoning, garlic powder, and onion powder. Mix well until the seasonings are fully incorporated and the mixture is smooth and fragrant.
- Spread half of the seasoned mayo mixture evenly over the bottom half of the bread, making sure to coat it generously. Then spread the remaining mayo mixture on the top half of the bread.
- Layer half of the sliced roast beef over the mayo on the bottom bread half, arranging the slices in a slightly overlapping pattern. Season lightly with salt and pepper.
- Add half of the sliced turkey over the roast beef layer, again arranging the slices neatly and seasoning to taste.
- Sprinkle half of the provolone cheese over the turkey layer, breaking slices as needed to cover evenly.
- Layer the sliced red bell peppers over the cheese, followed by the sliced green bell peppers and red onion. Season the vegetables lightly with salt and pepper.
- Add half of the roasted red peppers and half of the black olives over the fresh vegetables.
- Repeat the layers on top: remaining roast beef, remaining turkey, remaining provolone cheese, remaining roasted red peppers, and remaining black olives.
- Top with the sliced mozzarella cheese, arranging it in an even layer across the top. If using pepperoni, scatter the slices over the cheese before baking.
- Drizzle the Italian dressing over the top of the casserole, distributing it evenly. You want just enough to add flavor and moisture without making it soggy.
- Place the top bread half on top of all the filling layers, pressing down gently to help everything come together. The bread will nestle into the filling slightly.
- Cover the entire baking dish loosely with foil to prevent the top from browning too quickly while the inside cooks through.
- Bake for 25 minutes covered, then carefully remove the foil and bake for an additional 10-15 minutes until the top is golden brown and the cheese is melted and bubbly.
- Remove from the oven and let rest for 5 minutes before serving. This allows the layers to set slightly and makes it easier to cut and serve.
- Slice into squares and serve warm, garnished with fresh basil if desired. Serve any pan drippings on the side for dipping.
Pro Tips
Meat Selection: Feel free to use your favorite deli meats. Salami, ham, mortadella, or a combination work beautifully. The key is using quality sliced meats from the deli counter rather than pre-packaged options for superior flavor.
Cheese Variations: Experiment with different cheese combinations such as fresh mozzarella, aged provolone, sharp cheddar, or a blend of Italian cheeses. Freshly grated cheese melts more smoothly than pre-shredded varieties, which contain anti-caking agents.
Vegetable Customization: Add or substitute vegetables based on your preferences and what you have available. Artichoke hearts, sun-dried tomatoes, fresh spinach, or mushrooms all work wonderfully in this dish.
Italian Dressing: Homemade Italian dressing tends to have better flavor than bottled varieties, though either works. You can also use a light drizzle of olive oil mixed with red wine vinegar, Italian herbs, and garlic as an alternative.
Leftover Storage: Store any leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in a 325-degree oven, covered with foil, until warmed through. You can also slice and reheat individual portions in the microwave.
Serving Suggestions: Pair with a fresh green salad, garlic bread, or roasted vegetables. This dish also pairs well with tomato-based soups or a simple pasta salad for a complete meal.
Scaling the Recipe: To serve a smaller group, you can halve all ingredients and use an 8-inch square baking dish instead. Reduce cooking time by about 5 minutes.
Temperature Check: The casserole is properly cooked when the internal temperature reaches 165 degrees Fahrenheit and the cheese is fully melted and bubbly around the edges.
Frozen Option: You can freeze this casserole after assembly but before baking. Wrap tightly with plastic wrap and foil, then freeze for up to 2 months. Bake from frozen, adding about 20 minutes to the total cooking time.