preheat oven 450

heat 1tbs oil in large skillet over med-high. add beef & onion, cook. stir in worcestershire, garlic powder, and salt. set aside.

wisk milk & cornstarch in large saucepan. bring to a boil over med-high heat, wisk often, until bubbling and thick enough to coat back of spoon, 6-8mins total. remove from heat & stir cheddar, 3/4 salt until cheese is melted.

spread beef mixture in 9-by-13 inch or 3-quart baking dish. top with broccoli & poor cheese sauce evenly over the top.

combine potatoes, egg, pepper, & 1/4tps salt in med bowl. sprinkle over top. coat with cooking spray.

bake until bubbling & potatoes are begging to brown, about 40mins. sprinkle paprika.