Preheat oven to 300° F and line a baking sheet with parchment paper.
In a medium mixing bowl, whisk together the oil, maple syrup, cinnamon, and salt until combined.
Stir in oats and any additional add-ins, if desired, until completely coated.
Pour mixture on to prepared baking sheet in a thin, even layer. Bake at 300° F for 20 minutes, stirring halfway.
Remove from oven and allow to cool completely. It will become crispier as it cools. Store in an airtight container in a cool place for up to one month.