Preheat oven to 375°F (190°C). Lightly oil a baking dish.

Toss eggplant and zucchini with olive oil, salt, and pepper. Roast at 400°F (205°C) for 15-20 minutes until just tender.

Make béchamel: Melt butter in a saucepan over medium heat. Whisk in flour and cook 1 minute. Slowly add milk, whisking until smooth and thickened. Season with salt, pepper, and nutmeg.

Spread a thin layer of béchamel in the baking dish.

Add a layer of roasted vegetables, peas, béchamel, and a sprinkle of cheese.

Repeat layers, finishing with béchamel and remaining cheese on top.

Cover loosely with foil and bake for 30 minutes.

Uncover and bake 10-15 minutes more until bubbly and lightly golden.

Rest 10 minutes before slicing and serving.