Step 1

Preheat oven to 450 degrees F.

Step 2

Toss broccoli with 1 tablespoon oil in a large bowl. Spread out on a baking sheet and roast, stirring once halfway though, until just soft and browned in spots, about 15 minutes.

Step 3

Meanwhile, heat the remaining 1 tablespoon oil in a large skillet over medium heat. Add beef and onion and cook, breaking up the beef with a wooden spoon, until the beef is browned and the onion is softened, 10 to 12 minutes. Stir in Worcestershire, garlic powder and 1/4 teaspoon salt. Set aside.

Step 4

Whisk milk and cornstarch in a large saucepan. Bring to a boil over medium-high heat, whisking often, until bubbling and thickened enough to coat the back of a spoon, 6 to 8 minutes total. Remove from the heat and stir in Cheddar, 3/4 teaspoon salt and turmeric until the cheese is melted.

Step 5

Spread the beef mixture in a 9-by-13-inch (or similar 3-quart) baking dish. Top with the broccoli and pour the cheese sauce evenly over the top.

Step 6

Combine potatoes, egg, pepper and the remaining 1/4 teaspoon salt in a medium bowl. Sprinkle evenly over the casserole. Coat the top with cooking spray.

Step 7

Bake the casserole until it is bubbling and the potatoes are beginning to brown, about 40 minutes. Sprinkle with paprika. Let stand for 10 minutes before serving.