Cut the sweet potatoes in half and slice a sliver off the rounded side. This will prevent the halved pieces from rolling around the tray when you place it in the oven.
Generously spray both sides with cooking oil.
Place the sweet potatoes halved sided down on the lined baking sheet.
Place the baking sheet on the bottom rack in the oven. Bake for 35 minutes then flip and bake for 30 minutes.
Cool before transferring to a gladdest container. Store in the fridge for up to 5 days.