What happens when you take the most beloved comfort food duo and transform it into a warm, shareable casserole? Pure magic, that’s what. This Grilled Cheese and Tomato Soup Casserole captures everything we love about dunking a crispy, buttery sandwich into creamy tomato soup, but presents it in a way that feeds a crowd and brings people together around the dinner table. Layers of buttery bread and melted cheese mingle with a rich, homemade tomato base, creating a dish that’s part bread pudding, part grilled cheese, and entirely irresistible. This cozy casserole serves 8-10 people and turns a simple lunch into a memorable family meal that both kids and adults will request again and again.
Ingredients
For the tomato base:
- 3 tablespoons butter
- 1 large onion, diced
- 4 cloves garlic, minced
- 1 can (28 ounces) crushed tomatoes
- 1 can (14.5 ounces) diced tomatoes, drained
- 2 cups heavy cream
- 2 tablespoons tomato paste
- 1 teaspoon dried basil
- 1/2 teaspoon dried oregano
- 1 teaspoon salt
- 1/2 teaspoon black pepper
- 1 tablespoon sugar
For the bread and cheese layers:
- 10-12 slices thick-cut white or sourdough bread
- 6 tablespoons butter, softened
- 3 cups sharp cheddar cheese, grated
- 1 cup mozzarella cheese, grated
- 1/2 cup parmesan cheese, grated
For the custard mixture:
- 4 large eggs
- 1 cup whole milk
- 1/2 teaspoon salt
- 1/4 teaspoon black pepper
Building the Tomato Foundation
Preheat your oven to 375 degrees Fahrenheit and grease a 9×13 inch baking dish with butter. In a large saucepan, melt the butter over medium heat. Add the diced onion and cook for 5-6 minutes until softened and translucent. The onion should smell sweet and fragrant, not browned.
Add the minced garlic and cook for another minute until aromatic. Stir in the tomato paste and cook for 2 minutes, allowing it to deepen in color and develop richer flavor. This step concentrates the tomato taste and eliminates any raw paste flavor.
Pour in both the crushed and diced tomatoes, heavy cream, basil, oregano, salt, pepper, and sugar. Bring the mixture to a gentle simmer and let it cook for 10-12 minutes, stirring occasionally. The sauce should thicken slightly and the flavors should meld beautifully. Taste and adjust seasoning as needed. Remove from heat and set aside.
Preparing the Bread Layers
While the tomato mixture simmers, butter one side of each bread slice with the softened butter. This buttered side will become golden and crispy, just like the outside of a grilled cheese sandwich. Cut the bread slices in half diagonally to create triangles, which will layer more easily in the casserole dish.
In a separate bowl, combine all three cheeses – the sharp cheddar for flavor, mozzarella for stretch, and parmesan for that nutty depth. Mix them together so they’ll distribute evenly throughout the casserole.
Creating the Custard Base
In a medium bowl, whisk together the eggs, milk, salt, and pepper until smooth. This custard mixture will help bind everything together and give the casserole a rich, bread pudding-like texture that holds its shape when served.
Layering Your Masterpiece
Spread about one-third of the tomato mixture in the bottom of your prepared baking dish. Arrange half of the bread triangles over the tomato base, overlapping them slightly and placing them buttered-side up. Sprinkle half of the cheese mixture over the bread layer.
Pour half of the custard mixture evenly over the cheese, letting it soak into the bread. Spread another third of the tomato mixture over this layer, then repeat with the remaining bread, cheese, and custard. Finish with the final third of tomato mixture spread evenly on top.
Baking to Golden Perfection
Cover the dish tightly with aluminum foil and bake for 35 minutes. Remove the foil and continue baking for 15-20 minutes more, until the top is golden brown and the casserole is set in the center. A knife inserted in the middle should come out mostly clean, with just a few moist crumbs.
The surface should look beautifully golden with patches of melted cheese bubbling through the tomato layer. If you want extra browning, turn on the broiler for the last 2-3 minutes, watching carefully to prevent burning.
Resting and Serving
Let the casserole rest for 10-15 minutes before serving. This resting time allows everything to set properly and makes serving much easier. The casserole should hold its shape when cut but still be creamy and molten in the center.
Cut into generous squares and serve hot. Each portion should have distinct layers visible – the creamy tomato base, the soaked bread, and the golden, cheesy top. The texture should be similar to a savory bread pudding with the familiar flavors of your favorite grilled cheese and tomato soup combination.
Perfect Pairings
This hearty casserole pairs wonderfully with a simple green salad dressed with vinaigrette to cut through the richness. Crispy bacon crumbles or a side of roasted vegetables also complement the dish nicely. For drinks, consider serving with cold milk for the kids or a crisp white wine for the adults.
Make-Ahead Tips
This casserole can be assembled up to a day ahead and refrigerated before baking. If preparing ahead, add an extra 10-15 minutes to the covered baking time to account for the cold start. Leftovers reheat beautifully in the oven at 350 degrees for about 20 minutes, covered with foil to prevent the top from over-browning.
