After they have defrosted, use a quick chopper or food processor to shred the defrosted sprouts. Only pulse until the leaves have all separated from the sprouts.
Remove rice from pot, dump into a casserole dish, dump shredded Brussels sprouts into the rice-mix to combine. Top with approx. 3/4 cup of shredded Parmesan cheese. Season to taste with salt and pepper. Cover tightly with foil.
Bake covered at 375 degrees F for approx. 20 minutes, then remove the foil, add several pats of butter or margarine, and bake uncovered for an additional 15 minutes.
Stir, serve and enjoy!