1-First Step: Preheat the oven and get the baking dish ready Start by preheating your oven to 350°F (175°C). While the oven heats, prepare a 9×13-inch baking dish. This gives the baked Italian sub sandwiches enough room to fit side by side without crowding, which helps them heat evenly. If you are making these for a busy evening, this is the point where you can set out all your ingredients and slice the red onion if you have not done that already. Getting everything ready first keeps the assembly quick and smooth.

2-Second Step: Slice the hoagie rolls Take the 4 hoagie rolls and slice each one lengthwise, but do not cut all the way through. You want the rolls to open like a hinge so the fillings stay tucked inside. This style also makes the sandwich easier to handle after baking. Use a gentle sawing motion with a serrated knife so the bread does not tear. A soft but sturdy roll works best because it can soak up flavor without falling apart in the oven.

3-Third Step: Brush the inside with Italian dressing Brush the inside of each roll with 1/3 cup Italian dressing. This step adds moisture and a tangy, herby taste that runs through every bite. Spread it evenly so each sandwich gets a nice flavor boost. If you like a slightly lighter sandwich, you can use a little less dressing, but the full amount gives the best deli-style taste. The dressing also helps keep the bread from feeling dry after baking.

4-Fourth Step: Layer the meats and cheese On the bottom half of each roll, layer 3 slices sandwich-sized pepperoni, then 4 to 5 folded slices of turkey, and finally 3 folded slices provolone cheese. Folding the turkey and cheese helps build height and gives the sandwich a fuller, more satisfying texture. Try to spread the ingredients evenly so every bite has a good mix of meat and cheese. If you want a less rich version, use thinner layers, but keep enough filling so the sandwich still feels hearty.

5-Fifth Step: Add the vegetables and seasonings Top the filling with sliced red onion and sweet and hot salad peppers. Then sprinkle the seasonings across the sandwiches using 1/2 teaspoon pepper, 1/2 teaspoon salt, and 1/2 teaspoon oregano. Divide the seasoning evenly so each sub tastes balanced. For a little more brightness, you can add extra peppers or even a few sliced black olives. The mix of onion, peppers, and oregano gives the baked Italian sub sandwiches that familiar deli counter flavor many people love.

6-Sixth Step: Mix and brush the topping Melt 1 tablespoon butter with 1 tablespoon garlic salt in a microwave-safe bowl. Stir until the butter is melted and the garlic salt is mixed in well. Then brush this mixture over the top buns. This step adds a savory finish and helps the tops of the rolls turn golden and fragrant. It is a small touch, but it makes the final sandwich taste much richer.

7-Seventh Step: Bake until hot and melty Place the assembled subs in the prepared baking dish and bake for 20 minutes. The sandwiches should be heated through and the cheese should melt fully. If you want the tops a little crisper, you can bake them a few minutes longer, but watch closely so the bread does not dry out. The aroma will be a good sign that they are close to done. At this stage, the hoagie rolls should feel warm, the cheese should be soft, and the fillings should be hot all the way through.

8-Final Step: Serve while warm Carefully remove the baked Italian sub sandwiches from the oven and let them rest for a minute or two before serving. This makes slicing and handling easier. Serve them warm while the cheese is still soft and the bread is lightly toasted. These sandwiches pair nicely with a simple salad, chips, or a cozy side like au gratin potatoes. For another family-friendly meal idea, you could also try turkey and dressing on a day when you want something comforting and filling.