Whole wheat bread is made from whole wheat flour, which contains more fiber, vitamins, and minerals than refined white flour.

Bacon is the main source of protein in a BLT sandwich, as it is made from cured pork belly.

Sauerkraut is a fermented cabbage dish that is a key ingredient in a traditional Reuben sandwich.

Cheddar cheese is the most common type of cheese used in grilled cheese sandwiches due to its gooey texture and sharp flavor.

Mustard is a common condiment used in Cuban sandwiches, along with pickles, ham, and Swiss cheese.

Tofu is a common protein source used in vegetarian banh mi sandwiches, as it can be marinated and seasoned to mimic the flavor of meat.

Challah bread is a Jewish egg bread that is often used in Monte Cristo sandwiches, which are typically made with ham, cheese, and a sweet batter.

Bread is the main source of carbohydrates in a club sandwich, as it is made with multiple layers of bread.

Olives are a key ingredient in a traditional muffuletta sandwich, which is a New Orleans specialty made with Italian meats, cheeses, and a tangy olive salad.

Swiss cheese is the traditional cheese used in French dip sandwiches, which are made with roast beef and served with a flavorful dipping sauce.

Pita bread is the traditional bread used in gyro sandwiches, which are made with seasoned meat, vegetables, and a yogurt-based sauce.

Tuna is the main source of protein in a tuna salad sandwich, as it is made with canned or cooked tuna.

Pickles are a key ingredient in a traditional Cuban sandwich, along with ham, pork, Swiss cheese, and mustard.

Rye bread is the traditional bread used in patty melt sandwiches, which are made with ground beef, cheese, and grilled onions.

Mayonnaise is a common condiment used in BLT sandwiches, along with bacon, lettuce, and tomato.