If using fresh broccoli, wash and cut the florets. If using frozen, just measure the required amount.
In a large pot, bring about an inch of water to a boil. Place the broccoli in a steamer basket and cover with a lid. Steam for 5-7 minutes until tender but still vibrant green.
In a medium saucepan over medium heat, melt the butter. Once melted, whisk in the flour and cook for about 1 minute to create a roux.
Gradually add the milk to the roux, whisking constantly to avoid lumps. Continue cooking until the mixture thickens (about 3-5 minutes).
Once thickened, reduce the heat to low and stir in the shredded cheddar cheese, garlic powder, salt, and black pepper. Stir until the cheese is fully melted and the sauce is smooth.
Add the steamed broccoli to the cheese sauce and gently stir until the broccoli is evenly coated.
Transfer the cheesy broccoli to a serving dish and, if desired, sprinkle with paprika for a touch of color. Serve warm.