Summer Vegetable Gratin
If your garden is handing you more zucchini than you know what to do with, this Summer Vegetable Gratin is exactly what you need.
It is a layered vegetable bake that stacks yellow squash, zucchini, and tomatoes over a soft bed of shallots, garlic, and fresh herbs, then finishes under a blanket of freshly grated parmesan.
It looks like something you would order at a restaurant, and it comes together in one baking dish with about 15 minutes of hands on work.
I started making this gratin a few summers ago after a trip to the farmer’s market left me with a tote bag full of squash. My family is not always thrilled about plain steamed vegetables, but they went back for seconds of this one.
The parmesan on top turns golden and bubbly, and the tomatoes soften into little pockets of sweetness between the squash slices. It is the kind of dish that makes a regular weeknight dinner feel a little special.
Here is the short version of how it works. You soften 4 chopped shallots, or 2 small sweet onions, in 2 Tablespoons of extra virgin olive oil over medium heat for 5 to 7 minutes.
Then you add 4 cloves of garlic for 1 more minute, then stir in 1/4 cup of chopped fresh basil and 2 teaspoons of chopped fresh thyme. That herby mixture goes into the bottom of a baking dish that has been sprayed with nonstick spray.
Next you toss 2 medium yellow squash and 1 medium zucchini, both sliced 1/4 inch thick, with a drizzle of olive oil, salt, and pepper.
Then you arrange them in slightly slanted rows with 6 Roma tomatoes or 4 vine ripened tomatoes cut 3/4 inch thick. Season the top, cover with foil, and bake at 375 degrees for 30 to 35 minutes, until the vegetables are tender but not mushy.
Pull the foil off, sprinkle 3/4 cup of freshly grated parmesan over the top, and bake another 10 to 15 minutes until the cheese is golden and bubbly. Let the dish rest for 10 minutes before you slice it.
That resting step is worth respecting. Ten minutes off the heat lets everything settle, so the slices hold together and the juices stay in the dish instead of running across the plate.
If you cut into it straight from the oven, you will still get a delicious spoonful, but the layers will slide apart. I learned that one the hard way while rushing dinner to the table.
A few things I love about this recipe:
- It is meatless, egg free, gluten free, and low fat, so it fits a lot of different tables.
- The vegetables do the heavy lifting. Fresh basil and thyme are the only real flavor builders besides the parmesan.
- It bakes in one dish, which means one pan to wash and a very pretty centerpiece for a potluck.
- The parmesan crust is the part everyone fights over.
Keep your squash and zucchini slices at 1/4 inch and your tomato slices at 3/4 inch. Thinner squash turns to mush in the oven, while thicker tomato slices stay firm and juicy.
This gratin is a side dish, but it is a generous one. I like it next to grilled chicken, a piece of baked fish, or a simple plate of pasta with olive oil and garlic.
It also holds its own at a cookout with burgers and corn on the cob. Because it serves 6, it is an easy one to bring along when you are asked to contribute something to a summer gathering.
About the tomatoes: Roma tomatoes are excellent here because they are firm and not too watery, but vine ripened tomatoes work beautifully too. Pick whichever looks best at the store or the market that day.
If your tomatoes are on the smaller side, use a few more so the rows fill out. Same idea with the squash.
Two medium yellow squash and one medium zucchini filled my dish nicely, and if you happen to have extra, a slightly fuller dish bakes up just fine.
One more note on the pan. The recipe was written for a 7×11 inch baking dish, which is the same shape as an 11×7 inch dish. An 8×8 inch dish should also work if that is what you have in the cupboard.
Just keep in mind that a smaller, deeper dish means the vegetables will be piled higher and may need a few extra minutes under the foil before they turn tender.
Leftovers are a treat. I have been known to eat a cold slice straight from the fridge the next day, though a quick warm up in the oven brings the parmesan back to life. Cover the dish and refrigerate what you do not finish, then reheat gently so the cheese does not scorch.
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Ingredients
Everything here is easy to find in the summer, and most of it probably already lives in your kitchen. Here is what you need for 6 servings.
- 2 Tablespoons extra virgin olive oil, plus a little more for drizzling the squash
- 4 shallots, chopped, or 2 small sweet onions if you prefer a milder, sweeter base
- Salt and pepper, for seasoning at every stage
- 4 cloves garlic
- 1/4 cup chopped fresh basil
- 2 teaspoons chopped fresh thyme
- 6 Roma tomatoes, or 4 vine ripened tomatoes, sliced 3/4 inch thick
- 2 medium yellow squash, cut into 1/4 inch slices
- 1 medium zucchini, cut into 1/4 inch slices
- 3/4 cup freshly grated parmesan cheese
Ingredient tips: Grate the parmesan yourself if you can. Freshly grated cheese melts into a soft, golden crust, while the pre shredded kind tends to stay grainy.
Keep the basil and thyme fresh rather than dried, since they carry the whole flavor of the shallot layer. If you only have one of the two herbs on hand, use what you have and taste as you go.
And do not skip the salt and pepper at each stage. The vegetables need seasoning before they bake, not just after.
Directions
This comes together in four simple steps, and the oven does most of the work. Preheat the oven before you start so it is fully hot when the dish goes in.
- Preheat and prep the dish. Preheat the oven to 375 degrees. Spray a 7×11 inch baking dish with nonstick spray, then set it aside.
- Build the herby base. Heat 2 Tablespoons of extra virgin olive oil in a large skillet over medium heat. Add the shallots or onions, season with salt and pepper, and saute until softened, 5 to 7 minutes. Add the garlic and saute for 1 more minute. Add the fresh basil and thyme, then stir to combine. Transfer the mixture to the prepared baking dish and spread it into an even layer in the bottom.
- Layer and bake. Add the sliced zucchini and yellow squash to a large bowl, then drizzle lightly with extra virgin olive oil and season with salt and pepper. Layer the vegetables in slightly slanted rows until you run out of room or all the vegetables are used up, sliding the tomato slices in between the squash. Season the top with salt and pepper, then cover the baking dish with foil and bake for 30 to 35 minutes, or until the vegetables are tender when pierced with a knife. Remove the foil, then sprinkle the parmesan cheese on top. Return the dish to the oven uncovered and bake until the cheese is golden brown, 10 to 15 minutes.
- Rest and serve. Let the dish sit for 10 minutes before serving.
Watch the texture, not just the clock. The vegetables should be tender when a knife slides in easily, but not mushy. If your slices are still firm at 30 minutes, give them a few more minutes under the foil.
Work in rows. Standing the slices at a slight angle instead of laying them flat gives you that classic layered look, and it also lets the heat move between the slices so everything cooks evenly.
Save the parmesan for the end. It goes on after the foil comes off, so it melts and browns on top instead of steaming under the cover.
Let it rest. Ten minutes on the counter makes slicing much easier and keeps each portion neat.
Recipe details
This gratin takes 15 minutes of prep and 45 minutes in the oven, for a total of 1 hour, and it serves 6.
| Detail | Info |
|---|---|
| Prep time | 15 minutes |
| Cook time | 45 minutes |
| Total time | 1 hour |
| Servings | 6 |
| Oven temperature | 375 degrees F |
| Primary method | Bake |
The nutrition below is the source nutrition per serving, as published with the recipe.
| Nutrient | Amount per serving |
|---|---|
| Calories | 135 kcal |
| Carbohydrates | 10 g |
| Protein | 6 g |
| Fat | 9 g |
| Saturated fat | 3 g |
| Fiber | 2 g |
| Sugar | 5 g |
| Sodium | 228 mg |
| Cholesterol | 11 mg |
FAQs
What vegetables go in summer gratin?
This summer vegetable gratin features zucchini, yellow squash, and Roma or vine-ripened tomatoes as the main vegetables. The base is made with sauteed shallots and fresh herbs. You can also add eggplant or bell peppers if desired.
How do you keep summer vegetable gratin from getting watery?
To prevent a watery gratin, slice the zucchini and yellow squash uniformly into 1/4-inch pieces and lightly salt them before layering to draw out excess moisture. Also, use Roma tomatoes, which have firmer flesh and fewer seeds. Do not overcook the vegetables; bake covered until just tender.
What cheese is best on summer vegetable gratin?
Freshly grated parmesan cheese is the best choice for this gratin. It creates a golden, savory crust that complements the tender vegetables. Avoid pre-shredded parmesan, as it contains anti-caking agents that prevent smooth melting. Use 3/4 cup of freshly grated parmesan as directed in the recipe.
Can you make summer vegetable gratin ahead of time?
You can prepare the gratin up to the point of adding the cheese and then refrigerate it, covered, for up to 24 hours. When ready to bake, add the parmesan and bake as directed, adding a few extra minutes. Leftover baked gratin can be stored in the refrigerator for up to three days and reheated in a low oven.
Summer Vegetable Gratin
Summer Vegetable Gratin If your garden is handing you more zucchini than you know what to do with, this Summer Vegetable Gratin is exactly what you need. It is a layered vegetable bake that stacks yellow squash, zucchini, and tomatoes over a soft bed of shallots, garlic, and fresh herbs, then finishes under a blanket of freshly grated parmesan.
- Total Time: 60 min
- Yield: 6 1x
Ingredients
2 Tablespoons extra virgin olive oil
4 shallots, chopped
salt
pepper
4 cloves garlic
1/4 cup fresh basil, chopped
2 teaspoons fresh thyme, chopped
6 Roma tomatoes, sliced 3/4” thick
2 medium yellow squash, cut into 1/4 inch slices
1 medium zucchini, cut into 1/4 inch slices
3/4 cup parmesan cheese, freshly grated
Instructions
1-Preheat oven to 375 degrees: Preheat oven to 375 degrees. Spray a 7×11″ baking dish with nonstick spray then set aside.
2-Heat 2 Tablespoons extra virgin olive oil: Heat 2 Tablespoons extra virgin olive oil in a large skillet over medium heat. Add shallot or onions, season with salt and pepper, and then saute until softened, 5-7 minutes. Add garlic then saute for 1 more minute. Add fresh basil and thyme then stir to combine. Transfer mixture to prepared baking dish then spread into an even layer in the bottom.
3-Add sliced zucchini and yellow squash to: Add sliced zucchini and yellow squash to a large bowl then drizzle lightly with extra virgin olive oil and season with salt and pepper. Layer the vegetables in slightly slanted rows until you run out of room or all the vegetables are used up. Season the top with salt and pepper then cover the baking dish with foil and bake for 30-35 minutes, or until the vegetables are tender when pierced with a knife. Remove foil then sprinkle parmesan cheese on top. Return to oven uncovered then bake until cheese is golden brown, 10-15 minutes.
4-Let dish sit for 10 minutes before: Let dish sit for 10 minutes before serving.
- Prep Time: 15 min
- Cook Time: 45 min
- Method: bake
Nutrition
- Calories: 135kcal
- Sugar: 5g
- Sodium: 228mg
- Fat: 9g
- Saturated Fat: 3g
- Carbohydrates: 10g
- Fiber: 2g
- Protein: 6g
- Cholesterol: 11mg
