Tomato Gratin combines juicy, ripe tomatoes, fresh basil, toasted chunks of crusty bread, and Parmesan cheese in a simple baked casserole. It’s insanely good!
My absolute favorite time of the year is summer tomato season! There’s nothing better than a ripe tomato, freshly picked from the garden and still warm from the sun.
And the flavors – sweet and tart and savory – all in one. This easy Tomato Gratin plays up on all of those flavors by sauteing diced, fresh tomatoes with onions and garlic. Then mixing chunks of toasted bread and adding a sprinkle of salty Parmesan on top before the dish is baked.
The bottoms of crusty bread soak up some of the sweet, warm tomato juices, while the tops get toasted under the melted cheese. This gratin is so good – you’ll be tempted to make it every week for the rest of the summer!
What is a Gratin?
A gratin is a dish that is either baked or broiled in a shallow pan or dish with a topping of either cheese or breadcrumbs – or sometimes both, like today’s recipe. The top is distinctively crispy as it comes out of the oven.
The term gratin is derived from the French verb gratiner which means “to broil.”
Key ingredients and Substitutions
- Fresh garden tomatoes – Use large garden tomatoes of any variety. (This is a great way to use up an abundance of tomatoes from your garden).
- Baguette – Any crusty bread such as French baguette or a loaf of Ciabatta can be used.
- Olive oil – Use extra virgin olive oil for the best flavor.
- Garlic and onions – We used fresh garlic and red onion, however yellow or sweet onion, or even shallots can be used as a substitute in place of the red onions.
- Parmesan cheese – Try to buy an aged Parmesan cheese cut from a larger wheel if you can. (Avoid the jarred stuff – it just doesn’t compare in flavor or aroma.) Romano cheese can also be used instead.
Special supplies needed
- Large oven-safe skillet or braiser.
How do I make Tomato Gratin?
- Cut a baguette or loaf of crusty bread into large cubes. Toast in the large skillet with olive oil, salt and pepper. Set aside.
- Sauté onions and garlic with olive oil in the same skillet. After a few minutes, add diced tomatoes and seasonings, and stir to combine. Cook until bubbly.
- Remove the pan from the heat, then add about three-quarters of the previously-toasted bread cubes, pressing down into the tomatoes and their juices. Top with the remaining toasted baguette.
- Sprinkle the grated Parmesan cheese over the top, then bake until golden and crunchy, and the cheese is melted.
- Serve as a side dish with any meat or fish.
Chef’s Tip –
Toasting the baguette, then adding some to absorb the tomato juice and the rest to form a top crust is key to achieving a perfect, crispy gratin.
Frequently asked Questions
- Can I make this dish ahead of time? You can toast the bread ahead of time, as well as sauté the tomatoes, onions and garlic. Assemble before baking, but be sure to reheat the tomatoes
- How do I store any leftovers? We stored our leftovers covered in the refrigerator.
- How do I reheat any leftovers? We actually eat the leftovers cold, right out of the refrigerator – similar to a panzanella (bread salad). You can also reheat the leftovers in a warm oven – reassembling the remaining tomatoes in the bottom of a smaller pan, then adding the crispy bread on top.
You might enjoy these other tomato recipes:
- Tomato Jam
- Grilled Tomato Ciabatta
- Tomato Pie
- Green Tomato Relish
- Zucchini Tomato Italian Sausage Soup
1 16-ounce baguette or crusty loaf of bread
½ cup extra virgin olive oil, divided
2 teaspoons kosher salt, divided
1 teaspoon freshly ground black pepper, divided
½ cup red onion, diced
1 tablespoon fresh garlic, minced
3 pounds fresh garden tomatoes, cored and cut into large one-inch pieces (seeds and skin left in)
1 teaspoon granulated sugar
1 cup Parmesan cheese, grated
8 basil leaves, cut chiffonade (stack, roll and cut strips from one end to the other of the roll)
Preheat oven to 350 degrees F.
Cut the baguette into one-inch cubes and toss with ¼ cup of the olive oil, one teaspoon of the salt and a half teaspoon of the pepper.
In a large oven proof skillet over medium high heat, place the cubed bread and toast in the hot pan until browned and crunchy on all sides, about ten minutes.
Wipe the pan out and add the remaining oil and over medium heat, cook the onion and garlic for two to three minutes or until just starting to brown.
Add the cut-up tomatoes, remaining teaspoon of salt, remaining half teaspoon of pepper and the granulated sugar and cook for ten minutes letting it bubble uncovered.
Remove from heat and pour in ¾ of the toasted bread and press into the tomatoes, soaking up the liquid.
Sprinkle the rest of the bread over the top and then cover with the grated Parmesan cheese.
Bake 30 minutes then loosen the edges with a rubber spatula then bake ten more minutes.
The top will be golden and crunchy.
Let the pan rest for ten minutes, add the basil leaves then serve.
Keywords: Tomato Gratin