In a large pot, blanch the broccoli florets in boiling water for about 2 minutes until bright green. Drain and set aside.
In a mixing bowl, combine the cooked rice, cream of mushroom soup, milk, garlic powder, onion powder, and Dijon mustard. Mix well until fully combined.
Stir in the blanched broccoli and half of the shredded cheddar cheese. Season the mixture with salt and pepper to taste.
Transfer the rice and broccoli mixture to a greased 9x13-inch baking dish. Spread it evenly across the bottom.
In a separate bowl, combine the breadcrumbs with olive oil, mixing until the crumbs are evenly coated. Sprinkle the breadcrumb mixture over the rice and broccoli.
Top with the remaining shredded cheddar cheese.
Bake in the preheated oven for 25-30 minutes, or until bubbly and the top is golden brown.
Allow to cool for a few minutes before serving.
Notes
Serve hot, garnished with fresh parsley or chives.