Gather all ingredients. Preheat the oven to 350 degrees F (175 degrees C).
Cook instant rice as directed on box and cook broccoli as directed on package; drain.
Melt butter in a medium pan over medium heat. Add onions; cook and stir until softened, about 3 to 5 minutes.
Combine broccoli, rice, onion, soup, and cheese sauce together: season with salt and pepper. Transfer mixture into a 9x13-inch casserole dish.
Bake in the preheated oven until golden on top, 30 to 40 minutes.
