Traditional French Broccoli Gratin is a classic dish that combines tender broccoli florets with a creamy, cheesy sauce. The broccoli is blanched until just tender, then topped with a rich béchamel sauce made with butter, flour, milk, and Gruyère cheese. The dish is then baked until golden and bubbly, creating a deliciously comforting side dish or vegetarian main course. Serve this gratin alongside roasted meats or as a standalone dish with a green salad for a satisfying meal.