Preheat oven to 400 degrees. Grease a baking sheet with non-stick spray or olive oil and set aside.
Combine Brussels Sprouts, red potatoes, purple potatoes and olive oil in a large Ziploc bag and shake to coat. Add the Parmesan cheese, onion powder, garlic powder, salt and pepper to the bag and shake to coat.
Spread in an even layer on the baking sheet and bake for 20 minutes; turning on the broiler the last 1-2 minutes of cooking to lightly brown the Brussels Sprouts and potatoes. Serve immediately.
If you can not find purple potatoes you can substitue gold or more red. Store leftovers in fridge. This recipe serves six.