Grilled Cheese and Tomato Soup Casserole

Why separate grilled cheese and tomato soup when all you really want is the two served together? This grilled cheese and tomato soup casserole is the classic soup and sandwich pairing—rich gooey cheese, buttery bread, creamy tomatoes and a hint of basil—but baked all together in one dish. No dipping necessary!

Think of this as a bread pudding or overnight savory French toast bake, with soft cheesy sandwiches absorbing tomato soup-flavored custard. It takes just a handful of kitchen staples and minutes to make the thick tomato soup from scratch, and the three types of cheese in the sandwiches flood them with flavor.

Ingredients for Grilled Cheese and Tomato Soup Casserole

• Cheeses: Cheeses dominate this casserole, with cream cheese spread between the bread layers, slices of mozzarella laid on top of the sandwiches and shredded cheese sprinkled over the entire dish. Use reduced-fat and part-skim cheeses to keep the casserole from feeling too heavy.
• Basil: Dried basil gives tomato soup a traditional flavor and adds an herbal pop to the cream cheese spread.
• Bread: Cut a sturdy loaf like Italian, sourdough or rye into 1/2-inch-thick slices that will soak up the soup without falling apart. Soft pre-sliced sandwich bread will likely be too thin and stay mushy even when fully baked.
• Butter: Soften the butter before you spread it on the bread so your knife doesn’t tear into the slices.
• Tomato paste: Tomato paste has a richer flavor and thicker texture than tomato sauce or fresh tomatoes, which is why it’s an excellent way to add flavor to the custard.
• Seasonings: This tomato soup grilled cheese casserole recipe sticks with garlic, salt and pepper.
• Milk: Use 2% milk to make the pour-over soup sufficiently creamy. Skim milk might taste a little thin; whole milk or cream could make the dish overly rich.
• Eggs: Eggs turn the tomato soup into a thick sauce that coats the bread and sets up around the bread as the casserole bakes. Without eggs, the bread would become sodden and mushy.

Directions

Step 1: Make the sandwiches

Preheat the oven to 350°F. In a small bowl, mix the cream cheese and 1 teaspoon basil until blended. Spread the mixture onto six bread slices. Top with the sliced mozzarella cheese and the remaining bread.

Step 2: Arrange the sandwiches

Spread the outsides of the sandwiches with the butter. Arrange them in a greased 13×9-inch baking dish.

Editor’s Tip: Depending on the cut of your bread, you may need to overlap the sandwich edges to fit them in the baking dish. Gaps that let the soup ooze through the layers help the casserole cook more evenly than sandwiches crammed tightly into the pan.

Step 3: Make the soup base

In a small saucepan, combine the tomato paste, minced garlic, salt, pepper and remaining 1/2 teaspoon basil. Cook and stir over medium heat for one minute.

Editor’s Tip: For more intense tomato flavor, use this tomato paste technique: Add the tomato paste to the saucepan first and cook it for a few minutes, stirring, until it darkens slightly and releases a strong aroma. Then, add the other ingredients and cook one minute longer.

Step 4: Add the milk

Gradually whisk in the milk, and then bring the soup to a boil. Reduce the heat and simmer, uncovered, for four to five minutes or until thickened, stirring frequently. Remove the saucepan from the heat.

Step 5: Whisk in the eggs

In a large bowl, whisk the eggs. Gradually whisk in a third of the tomato and milk mixture until smooth. Stir in the remaining tomato and milk mixture.

Editor’s Tip: Add the hot tomato mixture in stages to temper the eggs, slowly bringing the ingredients to the same temperature. If you add the hot soup all at once, the eggs will curdle into unappealing clumps.

Step 6: Dress the sandwiches

Pour the soup over the sandwiches.

Sprinkle the casserole with the shredded cheese.

Editor’s Tip: Let the soup roll off the sandwiches and pool along the pan’s edges and in the spaces around the bread. The sandwiches will gradually absorb the liquid as they bake, making them less soggy than if you were to soak them in the soup.

Step 7: Bake the casserole

Bake, uncovered, until golden brown and the cheese melts, 25 to 30 minutes. Let the casserole stand for 10 minutes before serving.

Editor’s Tip: Check that the bread has crusted over on the top to your liking, and leave the casserole in the oven a few extra minutes if it still seems soggy. When this casserole comes out of the oven, let it sit for the full 10 minutes, if not a little longer. You’ll have a rich, creamy texture similar to a breakfast strata or a savory bread pudding.

Grilled Cheese and Tomato Soup Casserole Variations

• Toast the bread: For even crustier sandwiches, toast the bread before you assemble the layers. If you make toast without a toaster and instead use your stovetop and a lightly buttered skillet, you will create even more of a grilled cheese effect.
• Change the cheeses: Replace the cream cheese with chevre for its tangy goat cheese taste and the mozzarella slices with extra-sharp cheddar for over-the-top grilled cheese. Other cheese options include sliced Swiss or Colby cheese for the sandwiches and grated Parmesan for the casserole topping. For a toastier topping, stir a couple of tablespoons of panko bread crumbs into the shredded cheese.
• Cube the sandwiches: Cut the sandwiches into 1-inch cubes and then arrange them in the baking dish for a texture closer to tomato, sausage and cheddar bread pudding. The cubes will cook evenly in the soup, but if you set a few aside to tuck on top after you pour the soup into the baking dish, the bread will crisp up on the exposed corners.
• Change the seasonings: Add other herbs, like fresh or dried rosemary, oregano and thyme. Replace the basil with curry powder, both in the flavored cream cheese and in the soup. Puree a couple of tablespoons of caramelized onion and stir it into the tomato paste. Bump up the garlic, or replace it with soft roasted cloves.

How to Store Grilled Cheese and Tomato Soup Casserole

Let the grilled cheese and tomato soup casserole cool completely, then store it in an airtight container in the refrigerator. Let the casserole sit for at least 10 minutes in the pan so that the custardy soup sets up. Dish out the evening’s servings and then spread any leftover sandwiches on a baking tray to finish cooling.

How long does grilled cheese and tomato soup casserole last?

Grilled cheese and tomato soup casserole lasts three to four days in the refrigerator. The bread will become softer as it sits, and any soup surrounding it will firm up at fridge temperatures.

Can you freeze grilled cheese and tomato soup casserole?

You can freeze cooked grilled cheese and tomato soup casserole, but expect it to have a softer texture when reheated than when initially baked. Check that your baking dish is freezer-safe, and then wrap it well in storage wrap and aluminum foil. Freeze individual sandwiches in the same wrapping or an airtight container. The casserole will keep well in the freezer for about two months.

How do you reheat grilled cheese and tomato soup casserole?

If you froze the entire tomato soup grilled cheese casserole, partially thaw it in the refrigerator overnight. Set the baking dish of fridge-cold casserole on the counter while you preheat the oven to 350°, then cook until the sandwiches are heated through, about 20 minutes for refrigerated leftovers and a few additional minutes for partially thawed ones. Reheat individual leftover sandwiches in a baking dish in a toaster oven or in a skillet on the stovetop, as you would grilled cheese. In a microwave, leftovers would heat unevenly and turn soggy.

Grilled Cheese and Tomato Soup Casserole Tips

What’s the best bread for grilled cheese and tomato soup casserole?

Even if you think soft, pre-sliced white sandwich bread makes the perfect grilled cheese sandwich, go with something heartier to bake that grilled cheese into tomato soup. Crusty sourdough, French or Italian bread are good white choices, or use something with a stronger flavor, like rye bread or pumpernickel. Whichever type you choose, day-old bread will hold its shape better in this casserole than a freshly baked loaf.

What can you serve with grilled cheese and tomato soup casserole?

A crisp green salad makes a pleasing contrast to grilled cheese and tomato soup casserole, both in color and in texture. Kids (and adults) might prefer the crunch of air-fryer potato chips or refrigerator dill pickles. Lightly cooked vegetables also work well for a vegetarian meal. Serve the casserole as breakfast for dinner by topping each fully baked sandwich with slices of bacon and a fried egg. If treating the casserole as a side dish, pair it with a tender, juicy main course with a crispy coating, like tasty onion chicken or Dijon-crusted fish.