Prepare the broccoli: Steam or blanch broccoli florets for 2–3 minutes until bright green and slightly tender. Drain well and set aside.
Make the cheese sauce: In a large saucepan over medium heat, melt butter. Add diced onion and sauté until soft and translucent, about 3–4 minutes.
Stir in the flour and cook for 1 minute, whisking constantly to form a roux.
Slowly pour in the milk, whisking continuously until the sauce thickens and becomes smooth.
Add cream cheese, paprika, dry mustard, garlic powder, and black pepper. Stir until melted and creamy.
Remove from heat and stir in 1 cup of shredded cheddar cheese until smooth and fully melted. Adjust salt to taste.
Combine: In a large mixing bowl, gently fold together the cooked rice, steamed broccoli, and cheese sauce until well-coated.
Assemble: Transfer mixture into a lightly greased baking dish (about 9x13 inches). Sprinkle the remaining 1 cup of cheddar cheese evenly on top.
Bake: Bake in a preheated oven at 350°F (175°C) for 25–30 minutes, or until hot and bubbly with a golden top.
Serve: Let it rest for 5 minutes before serving. Enjoy as a cozy main or side dish!