I started cooking all of my fresh and frozen vegetables this way. My Hubby loves the brussel sprouts cooked this way. I had them at a friend's house for dinner, and fell in love with the idea immediately. My friend's and family love it!!
Preheat oven to 400 degrees. Spray pan with olive oil Pam. Add frozen brussel sprouts, chopped onion and drizzle with extra virgin olive oil. Place small bits of butter on top of brussel sprouts. Season with garlic pepper. Bake for 40 to 45 minutes until tender.