Ingredients:
- 3 lbs medium Zucchini
- 1 tsp Kosher Salt
- 3 Tbsp Unsalted Butter
- 3 Tbsp All-Purpose Flour
- 2 cups warm Whole Milk
- Pinch Ground Nutmeg
- 1/4 tsp White Pepper
- 1 cup grated Gruyère Cheese
- 1/2 cup grated Parmesan Cheese
- 1 tsp Fresh Thyme Leaves
- 1/2 cup Panko Breadcrumbs
- 1 Tbsp extra virgin Olive Oil
- 1 Tbsp chopped Fresh Parsley
Instructions:
- Preheat oven to 375°F (190°C). Lightly salt the thinly sliced zucchini rounds and let sit in a colander for 15 minutes to draw out excess water. Pat thoroughly dry with kitchen towels.
- Quickly sauté the dried zucchini in a hot, dry skillet in batches for 1-2 minutes per side just to soften slightly. Set aside.
- Make the Roux: Melt butter in a medium saucepan over medium heat. Whisk in the flour and cook for 1 minute until it smells slightly nutty.
- Build the Béchamel: Gradually whisk in the warm milk until smooth. Bring to a gentle simmer, whisking constantly until the sauce thickens enough to coat the back of a spoon. Remove from heat.
- Finish the Cheese Sauce: Stir in the grated Gruyère, Parmesan, nutmeg, white pepper, and fresh thyme. Taste and adjust seasoning.
- Assemble the Gratin: Lightly grease a 9x13 inch baking dish. Layer half of the zucchini slices evenly in the dish, pour half of the cheese sauce over them, and repeat with the remaining zucchini and sauce.
- Prepare the Topping: In a small bowl, toss the Panko breadcrumbs with olive oil and fresh parsley. Sprinkle evenly over the top layer of the gratin.
- Bake for 30–35 minutes, or until the sauce is bubbling thickly and the topping is deep golden brown.
- Rest and Serve: Let the gratin rest for 10 minutes before serving so it sets up nicely.