Vegetable Gratin

Preheat oven to 375°F. Prepare a 9x13 inch baking dish by lightly greasing it with butter or oil.

Slice zucchini into 1/4-inch rounds. Dice onion and mince garlic. Set aside.

In a medium saucepan, melt 2 tbsp butter over medium heat. Add onion and cook until softened, about 4 minutes. Stir in garlic and cook 1 minute more until fragrant.

Sprinkle flour over the onion mixture and stir constantly for 1–2 minutes to cook out the raw flour taste, forming a light roux.

Gradually whisk in milk and vegetable broth, stirring constantly to prevent lumps. Cook over medium heat, stirring occasionally, until the sauce thickens (about 5–7 minutes). It should coat the back of a spoon.

Remove from heat. Stir in 1/2 cup parmesan cheese and thyme. Season generously with salt and black pepper to taste.

Spread a thin layer of cheese sauce on the bottom of the prepared baking dish.

Arrange zucchini slices in a single overlapping layer over the sauce. Pour about one-third of the remaining sauce evenly over the vegetables.

Repeat layering: vegetables, then sauce, until all zucchini and sauce are used, ending with a final thin layer of sauce on top.

In a small bowl, toss breadcrumbs with the remaining 1 tbsp melted butter and 1/4 cup parmesan cheese. Scatter evenly over the top of the gratin.

Bake at 375°F for 30–35 minutes until the vegetables are tender, the sauce bubbles gently at the edges, and the breadcrumb topping is golden brown.

Remove from oven and let rest 5 minutes. Garnish with fresh chopped parsley if desired. Serve warm as a side dish.