Preheat oven to 425 degrees F.
Line baking sheet with parchment. Place sweet potato slices on the sheet.
Sprinkle the sweet potato slices with a pinch of salt, ¼ teaspoon cinnamon, and 2 teaspoons brown sugar. Spray the slices with cooking oil.
Bake at 425 for 15 minutes.
Top each slice with 2 - 3 mini marshmallows.
Broil 1 ½ minutes, or until marshmallows are toasted.