Ingredients
- Medium Zucchini (about 2 lbs / 1 kg): The star of the gratin. Choose firm, smooth-skinned zucchini. You will be slicing them into uniform rounds for even cooking and a beautiful layered presentation.
- Roma Tomatoes (about 1.5 lbs / 700g): Essential for their lower water content and meaty texture, which prevents the gratin from becoming too soggy. Their concentrated flavor deepens beautifully when baked.
- Yellow Onion (1 large): This forms the aromatic base of the dish, providing a deep, savory sweetness that complements the other vegetables perfectly.
- Garlic (4 cloves): Finely minced, this adds a pungent, aromatic kick that is crucial for the gratin’s flavor profile. Don’t be shy with the garlic!
- Olive Oil (3 tablespoons, divided): A good quality extra virgin olive oil is used to sauté the aromatics and to drizzle over the top, adding richness and helping the top to brown.
- Fresh Thyme (1 tablespoon, chopped): Its earthy, slightly minty flavor is a classic pairing with both zucchini and tomatoes.
- Fresh Basil (1/4 cup, chopped or torn): Added towards the end, basil provides a fresh, sweet, and slightly peppery note that brightens the entire dish.
- Shredded Mozzarella Cheese (1 cup / 115g): The workhorse for that glorious, gooey cheese pull. A low-moisture mozzarella is best for optimal melting without adding excess water.
- Grated Parmesan Cheese (1/2 cup / 50g): This adds a sharp, salty, and nutty flavor to the topping, creating a more complex cheese crust that browns beautifully.
- Panko Breadcrumbs (1/2 cup): These Japanese-style breadcrumbs are lighter and flakier than traditional breadcrumbs, guaranteeing an extra crispy, golden topping.
- Salt and Black Pepper (to taste): Crucial for seasoning every layer and drawing out the natural flavors of the vegetables.
Instructions
- Preheat and Prepare the Dish: Preheat your oven to 400°F (200°C). Lightly grease a 9×13 inch (or a similar-sized 2-quart) baking dish with olive oil or butter. This will prevent the gratin from sticking and make cleanup easier.
- The Crucial Zucchini Prep: This step is the secret to avoiding a watery gratin. Slice the zucchini into uniform 1/4-inch (about 1/2 cm) rounds. Place the slices in a colander set over a bowl or in the sink. Sprinkle them generously with about 1 teaspoon of salt and toss to coat. Let them sit for 20-30 minutes. You will see beads of water forming on the surface. This process, called disgorging, draws out excess moisture. After 30 minutes, gently pat the zucchini slices completely dry with paper towels. Do not rinse them.
- Prepare the Tomatoes and Aromatics: While the zucchini is resting, slice the Roma tomatoes into 1/4-inch rounds, similar to the zucchini. Finely chop the yellow onion and mince the garlic cloves.
- Build the Flavor Base: Heat 2 tablespoons of olive oil in a skillet over medium heat. Add the chopped onion and cook, stirring occasionally, until it becomes soft and translucent, about 5-7 minutes. Add the minced garlic and chopped fresh thyme and cook for another minute until fragrant. Be careful not to burn the garlic. Spread this aromatic onion and garlic mixture evenly over the bottom of your prepared baking dish. This layer is the foundation of your gratin’s flavor.
- Layer the Vegetables: Now for the artistic part. Arrange the dried zucchini slices and tomato slices vertically in the baking dish, alternating them in an overlapping pattern (e.g., zucchini, tomato, zucchini, tomato). This creates a beautiful shingled or domino effect. Pack them in snugly. Season the entire arrangement generously with salt and fresh black pepper.
- Prepare the Topping: In a small bowl, combine the shredded mozzarella, grated Parmesan, and Panko breadcrumbs. Use your fingers to toss everything together until it’s well mixed. This combination ensures you get both a gooey melt from the mozzarella and a sharp, crispy crust from the Parmesan and Panko.
- Top and Drizzle: Sprinkle the cheese and breadcrumb mixture evenly over the top of the layered vegetables, making sure to get into all the nooks and crannies. Drizzle the remaining 1 tablespoon of olive oil over the topping. This helps the breadcrumbs and cheese turn a beautiful golden brown.
- Bake to Perfection: Place the baking dish in the preheated oven. Bake for 30-40 minutes, or until the vegetables are tender when pierced with a knife, the sauce is bubbly, and the topping is deeply golden brown and crispy. If the top starts to brown too quickly before the vegetables are fully cooked, you can loosely tent it with a piece of aluminum foil for the last 10-15 minutes of baking.
- Rest and Garnish: This is a vital final step. Remove the gratin from the oven and let it rest for at least 10-15 minutes before serving. This allows the gratin to set up, making it easier to serve and allowing the flavors to meld together. Just before serving, sprinkle the fresh chopped basil over the top. The residual heat will release its incredible aroma. Serve warm and enjoy!
Nutrition
- Serving Size: one normal portion
- Calories: 195
- Saturated Fat: 5g
- Carbohydrates: 12g
- Fiber: 4g
- Protein: 9g