Adjust the oven rack to the middle position, and preheat oven to 425°F.
Steam Brussels sprouts by filling a large pot with about 2 cups of water and place a steamer basket in the bottom.
Bring the water to a boil. Place the Brussel sprouts into the steamer basket.
Cover the pot and steam until the Brussels sprouts are fork tender (6 minutes).
Meanwhile, in a large bowl add cream cheese, half-half cream, garlic powder, onion powder, salt and freshly ground black pepper. Mix everything well to combine all the ingredients together.
Remove the Brussels sprouts from the heat and place in the cream cheese mixture bowl. It’s not necessary to let Brussels sprouts cool down. The hot Brussels sprouts will help to melt the cheese.
Spoon the Brussels sprouts mixture into an oiled casserole dish and top with mozzarella cheese. Bake uncovered for 10 minutes or until the cheese is melted.
If you want the Brussels sprouts to be a little bit browned, you can turn the broiler on high for the final 3 minutes and broil it. Keep a close eye on it, so that it does not burn.
Before serving, top with fresh chopped parsley.