in a gallon sized ziploc bag, add the garlic, olive oil, butter, garlic salt, and Italian seasoning along with the diced sweet potatoes. Seal the bag and toss until well coated.
add in the Parmesan cheese, seal again and shake until coated.
Pour out of the bag on a foil lined baking sheet and spread out evenly. Bake at 400 degrees for 18-20 minutes until tender.