Place broccoli florets in a microwave proof bowl with 1 Tbsp water. Cover bowl with plastic wrap leaving a small vent for steam. Microwave broccoli until it begins to soften and is halfway cooked, about 3-4 minutes. Uncover, drain and set aside.
Preheat oven to 350 degrees. Grease a 13X9 baking dish.
Melt butter over medium heat. Add the onion and cook until translucent, about 3-4 minutes. Add garlic and cook until fragrant, about 1 minute. Sprinkle over the flour, dry mustard and cayenne and stir to mix it in well. Cook 1 minute.
Add the milk, stirring constantly, until thickened, about 2 minutes. Add the cream cheese and the parmesan, stirring until melted and totally combined. Stir in the pepper, salt and paprika. Add the processed cheese stirring until completely melted. Then add 1 cup of the cheddar cheese stirring until melted. Lastly fold in the broccoli into the cheese sauce. Remove from heat.
In the baking dish, spread half the rice over the bottom of the dish. Top with half the broccoli cheese sauce. Repeat spreading the last half of the rice, and then top with remaining broccoli cheese sauce. Sprinkle the remaining 1 cup of shredded cheddar cheese over the top.
Bake about 30 minutes until bubbly. Let rest 10-15 minutes before serving.
Enjoy!