Summer Vegetable Gratin: A Taste of Sunshine on Your Plate

I can still vividly remember the aroma that filled my brother’s home that Christmas in 2009. Snow was falling outside, a fire crackled merrily in the hearth, and the star of the show? Not a roasted bird, but a vibrant, bubbling Summer Vegetable Gratin. It was unexpected, delightful, and proved that sometimes, the best holiday meals are the ones that break the mold. Despite being surrounded by traditional holiday fare, I found myself returning to that dish again and again, savoring the concentrated flavors of summer captured within its golden crust. It was a reminder that good food transcends seasons and that vegetables, when prepared with love and care, can truly steal the show.

Recipe Overview

• Prep Time: 1 hour 25 minutes
• Cook Time: 50 minutes
• Total Time: 2 hours 15 minutes
• Servings: 4-6
• Yield: 1 gratin
• Dietary Type: Vegetarian (can be made vegan)

Ingredients

• 5 teaspoons extra virgin olive oil
• 1 lb zucchini, ends trimmed and sliced crosswise into 1/4 inch thick slices
• 1 lb summer squash (yellow), ends trimmed and sliced crosswise into 1/4 inch thick slices
• 2 teaspoons table salt
• 1 1/2 lbs tomatoes, ripe and sliced 1/4 inch thick (3-4 large)
• 2 medium onions, halved lengthwise and sliced thin (about 3 cups)
• 3/4 teaspoon ground black pepper
• 2 medium garlic cloves, minced (or pressed through garlic press, about 2 teaspoons)
• 1 tablespoon fresh thyme leaves, minced
• 1 large slice white bread, torn into quarters
• 2 ounces Parmesan cheese, grated (about 1 cup)
• 2 medium shallots, minced (about 1/4 cup)
• 1/4 cup fresh basil leaves, chopped

Equipment Needed

• 13- by 9-inch baking dish
• Large bowl
• Colander
• Paper towels
• 12-inch non-stick skillet
• Small bowl
• Food processor or blender

Instructions

1. Adjust oven rack to upper-middle position and heat oven to 400 degrees. Brush a 13- by 9-inch baking dish with 1 teaspoon olive oil; set aside.

2. Toss the zucchini and squash slices with 1 teaspoon salt in a large bowl. Transfer to a colander set over a bowl. Let stand until the zucchini and squash release at least 3 tablespoons of liquid, about 45 minutes. This step is crucial for preventing a soggy gratin. The salt draws out excess moisture, concentrating the vegetables’ natural flavors.

3. Arrange the zucchini and squash slices on a triple layer of paper towels. Cover with another triple layer of paper towels and firmly press each slice to remove as much liquid as possible. Be thorough; the drier the vegetables, the better the final texture.

4. Meanwhile, place the tomato slices in a single layer on a double layer of paper towels and sprinkle evenly with 1/2 teaspoon salt. Let stand for 30 minutes. Place a second double layer of paper towels on top of the tomatoes and press firmly to dry. Just like with the zucchini and squash, this step removes excess moisture from the tomatoes, preventing a watery gratin.

5. While the vegetables are draining, heat 1 teaspoon olive oil in a 12-inch non-stick skillet over medium heat until shimmering. Add the onions, the remaining 1/2 teaspoon salt, and 1/4 teaspoon pepper; cook, stirring occasionally, until the onions are softened and dark golden brown, 20 to 25 minutes. Patience is key here. Don’t rush the caramelization process; those beautifully browned onions add incredible depth of flavor to the gratin.

6. Set the caramelized onions aside.

7. Combine the garlic, 2 teaspoons olive oil, the remaining 1/2 teaspoon pepper, and thyme in a small bowl. This aromatic mixture will infuse the vegetables with flavor.

8. In a large bowl, toss the zucchini and squash with half of the garlic-oil mixture, then arrange in the greased baking dish. Spread them in a single, even layer.

9. Arrange the caramelized onions in an even layer over the squash.

10. Slightly overlap the tomato slices in a single layer on top of the onions.

11. Spoon the remaining garlic-oil mixture evenly over the tomatoes.

12. Bake until the vegetables are tender and the tomatoes are starting to brown on the edges, 40-45 minutes.

13. Meanwhile, process the bread in a food processor or blender until finely ground (about 10 seconds). You should have about 1 cup of crumbs.

14. Combine the bread crumbs, the remaining 1 teaspoon olive oil, Parmesan cheese, and shallots in a medium bowl. Mix well.

15. Remove the baking dish from the oven and increase the heat to 450 degrees.

16. Sprinkle the bread crumb mixture evenly on top of the tomatoes.

17. Bake until bubbling and the cheese is lightly browned, 5-10 minutes. Keep a close eye on it during this final stage to prevent burning.

18. Sprinkle with basil and let sit at room temperature for 10 minutes before serving. This allows the gratin to set slightly and the flavors to meld together.

Expert Tips & Tricks

• Pre-salting the vegetables is non-negotiable. It’s the key to preventing a soggy gratin and concentrating the flavors. Don’t skip this step!
• For a richer flavor, use a high-quality aged Parmesan cheese.
• If you don’t have fresh thyme, you can substitute 1 teaspoon of dried thyme.
• Feel free to add other vegetables to the gratin, such as eggplant or bell peppers. Just be sure to slice them thinly and pre-salt them as well.
• If the bread crumb topping starts to brown too quickly, tent the baking dish with foil.

Serving & Storage Suggestions

This Summer Vegetable Gratin is delicious served warm as a vegetarian main course or as a flavorful side dish alongside grilled chicken, fish, or meat. A crusty loaf of bread is perfect for soaking up the delicious juices.

Leftovers can be stored in an airtight container in the refrigerator for up to 3 days. To reheat, bake in a preheated oven at 350 degrees until warmed through, or microwave in short intervals.

While the gratin is best enjoyed fresh, it can be frozen for up to 2 months. Thaw overnight in the refrigerator before reheating. The texture may be slightly softer after freezing and thawing, but the flavor will still be delicious.

Nutritional Information

Nutrient	Amount per Serving	% Daily Value
Calories	230.9 kcal	N/A
Calories from Fat	98 g	43%
Total Fat	10.9 g	16%
Saturated Fat	3.5 g	17%
Cholesterol	12.5 mg	4%
Sodium	1441.8 mg	60%
Total Carbohydrate	25.7 g	8%
Dietary Fiber	5.8 g	23%
Sugars	12.6 g	N/A
Protein	11.3 g	22%

Note: Nutritional information is an estimate and may vary based on specific ingredients and preparation methods.

Variations & Substitutions

• Vegan Version: Omit the Parmesan cheese or substitute with a vegan Parmesan alternative. Nutritional yeast can also add a cheesy flavor.
• Gluten-Free: Use gluten-free bread to make the bread crumbs.
• Spicy Kick: Add a pinch of red pepper flakes to the garlic-oil mixture for a hint of heat.
• Herb Variations: Experiment with different herbs, such as rosemary, oregano, or marjoram.
• Cheese Variations: Use different types of cheese, such as Gruyere, mozzarella, or Fontina.
• Seasonal Adaptation: In the fall, substitute the zucchini and squash with butternut squash or pumpkin.

FAQs (Frequently Asked Questions)

Q: Can I make this gratin ahead of time?

A: Yes! You can assemble the gratin up to the point of baking and store it covered in the refrigerator for up to 24 hours. Add the breadcrumb topping just before baking.

Q: Why is it important to remove the excess moisture from the vegetables?

A: Removing excess moisture prevents the gratin from becoming watery and ensures that the vegetables roast properly.

Q: Can I use frozen vegetables in this recipe?

A: I don’t recommend using frozen vegetables, as they tend to release too much moisture and can result in a soggy gratin.

Q: What if I don’t have a food processor for the bread crumbs?

A: You can use a blender or simply crush the bread by hand. The crumbs don’t need to be perfectly uniform.

Q: Can I add other vegetables to this gratin?

A: Absolutely! Eggplant, bell peppers, and mushrooms are all great additions. Just be sure to slice them thinly and pre-salt them if necessary.

Final Thoughts

This Summer Vegetable Gratin is more than just a recipe; it’s a celebration of fresh, seasonal produce. It’s a dish that’s both comforting and elegant, perfect for a casual weeknight dinner or a special occasion. Don’t be afraid to experiment with different vegetables and herbs to create your own unique version. So, gather your ingredients, preheat your oven, and get ready to experience a taste of sunshine on your plate. I encourage you to try this recipe and share your feedback. Pair it with a crisp white wine for a truly delightful culinary experience!