Preheat oven to 350˚F (180˚C). Line a rimmed baking sheet with parchment or lightly grease.
In a large microwave-safe bowl, combine the peanut butter and honey. Microwave until softened enough to whisk until smooth, about 20 seconds. Stir in the cinnamon and vanilla extract. Fold in the oats until well-coated.
Spread the oats in an even layer on the prepared baking sheet. Bake in preheated oven until lightly golden, about 8 minutes. Cook until room temperature and crisp before storing in an airtight container.