Ingredients

• 2 zucchini, sliced into 1/4-inch rounds
• 1 eggplant, sliced into 1/4-inch rounds
• 3 waxy potatoes, sliced into 1/8-inch rounds
• 4 tomatoes, sliced into 1/4-inch rounds
• 4 tablespoon butter
• 3 tablespoon all-purpose flour
• 2 cup whole milk
• 0.5 teaspoon salt
• 0.25 teaspoon black pepper, freshly ground
• 0.25 teaspoon nutmeg, freshly grated
• 1 cup Gruyère cheese, shredded
• 2 garlic, minced
• 1 tablespoon fresh thyme, leaves only
• 1 tablespoon fresh parsley, finely chopped
• 2 tablespoon olive oil

Steps

1. Preheat oven to 375°F.
2. Slice zucchini into 1/4-inch rounds and place on paper towels. Sprinkle lightly with salt and let sit for 10 minutes to release excess moisture, then pat dry.
3. Slice eggplant into 1/4-inch rounds, salt lightly, and let sit for 10 minutes. Pat dry with paper towels.
4. Slice potatoes thinly (1/8-inch) using a sharp knife or mandoline. Keep in a bowl of cold water to prevent browning.
5. Slice tomatoes into 1/4-inch rounds and set aside on a clean surface.
6. Mince garlic cloves finely and chop fresh thyme leaves and parsley.
7. Shred Gruyère cheese and set aside.
8. Drain potatoes and pat dry thoroughly with paper towels.
9. Prepare béchamel sauce: melt 4 tablespoons butter in a large pot over medium heat.
10. Add 3 tablespoons flour to the melted butter and whisk constantly for 2 minutes to create a roux, stirring to ensure no lumps form.
11. Gradually add 2 cups whole milk while whisking continuously to avoid lumps.
12. Continue whisking until the béchamel thickens, about 5 minutes. The sauce should coat the back of a spoon.
13. Remove from heat and stir in minced garlic, 1/2 teaspoon salt, 1/4 teaspoon black pepper, and 1/4 teaspoon nutmeg. Taste and adjust seasoning if needed.
14. Lightly brush the bottom of a 9x13 inch baking dish with olive oil.
15. Spread a thin layer of béchamel sauce (about 1/4 cup) on the bottom of the prepared baking dish.
16. Arrange potato slices in a single overlapping layer on the béchamel, then pour 1/4 of the remaining béchamel over potatoes.
17. Layer zucchini slices in overlapping rows, sprinkle with 1/4 of the thyme, then cover with 1/4 of remaining béchamel.
18. Layer eggplant slices in overlapping rows, sprinkle with 1/4 of the thyme, then cover with 1/4 of remaining béchamel.
19. Arrange tomato slices on top in overlapping rows, sprinkle with remaining thyme, and cover with remaining béchamel sauce.
20. Sprinkle shredded Gruyère cheese evenly over the top layer.
21. Place baking dish in preheated 375°F oven and bake for 50–55 minutes until the top is golden brown and bubbling at the edges, and vegetables are tender when pierced with a knife.
22. Remove from oven and let rest for 5 minutes. Garnish with fresh parsley before serving.