A summer tomato gratin should burst with concentrated, bright tomato flavour and contrasting firm texture from the bread, but most recipes lead to mushy results. Not this one.
Starting our gratin on the stovetop initiated the breakdown of the tomatoes, drove off some moisture that would otherwise have sogged out the bread, and shortened the overall cooking time. We finished the dish in the dry, even heat of the oven.
Toasting large cubes of a crusty artisan-style baguette ensured that the bread didn’t get too soggy once combined with the tomatoes. After toasting the bread, we added the coarsely chopped tomatoes as well as garlic, a small amount of sugar, and salt and pepper. Just before moving the skillet to the oven, we folded in most of the toasted bread and scattered the remainder over the top along with some Parmesan to create a crusty, savory topping that contrasted with the custardy interior.
A scattering of fresh basil provided colour and bright flavour. The success of this recipe depends on using ripe, in-season tomatoes. Do not use plum tomatoes, which contain less juice than regular round tomatoes and will result in a dry gratin. You can serve the gratin hot, warm, or at room temperature. You will need a 12-inch oven-safe skillet for this recipe.
BEST SUMMER TOMATO GRATIN
Start to finish: 1 hour, 15 minutes
6 tablespoons extra-virgin olive oil
6 ounces crusty baguette, cut into 3/4 inch pieces (4 cups)
3 garlic cloves, sliced thin
3 pounds ripe tomatoes, cored and cut into 3/4 inch pieces
2 teaspoons sugar
1 teaspoon salt
1 teaspoon pepper
1 1/2 ounces Parmesan cheese, grated (3/4 cup)
2 tablespoons chopped fresh basil
Adjust oven rack to middle position and heat oven to 350 F. Heat 1/4 cup oil in 12-inch oven-safe skillet over medium-low heat until shimmering. Add bread and stir to coat. Cook, stirring constantly, until bread is browned and toasted, about 5 minutes; transfer to bowl.
Cook remaining 2 tablespoons oil and garlic in now-empty skillet over low heat, stirring constantly, until garlic is golden at edges, 30 to 60 seconds. Stir in tomatoes, sugar, salt, and pepper. Increase heat to medium-high and cook, stirring occasionally, until tomatoes have started to break down and have released enough juice to be mostly submerged, 8 to 10 minutes.
Off heat, gently stir in 3 cups bread until completely moistened and evenly distributed. Using spatula, press down on bread until completely submerged. Arrange remaining 1 cup bread evenly over surface, pressing to partially submerge. Sprinkle evenly with Parmesan.
Transfer skillet to oven and bake until top of gratin is deeply browned, tomatoes are bubbling, and juice has reduced, 40 to 45 minutes. After 30 minutes, run spatula around edge of skillet to loosen crust and release any juice underneath. (Gratin will appear loose and jiggle around outer edges but will thicken as it cools.)
Remove skillet from oven and let sit for 15 minutes. Sprinkle with basil and serve.