Preheat oven to 300℉. Line a baking sheet with parchment paper and set aside.
In a large bowl, add old fashioned oats, sesame seeds, and pepitas. Stir to combine and set aside.
In a small saucepan over medium heat, add tahini, maple syrup, sesame oil, cardamom, cinnamon, and salt. Stir until tahini has melted and mixture is thin and pourable. Alternatively, carefully warm in the microwave in 30 second increments.
Drizzle tahini mixture over oats and toss until evenly coated. Pour mixture onto prepared baking sheet and spread into a single layer.
Bake for 30-35 minutes, rotating pan once halfway through. If edges are browning quickly, give your oats a quick toss and press back into an even layer.
Remove from oven and allow to cool completely on baking sheet. Granola will harden more as it cools. Store in an airtight container at room temperature.
Notes
Storage: Cooked granola will keep for 2 weeks or more in a tightly sealed container at room temperature.
Sweetener substitutes: Maple syrup can be substituted with honey, brown sugar, or granulated sugar.
How to make clumpy granola: The maple syrup and tahini create a glue that helps the granola stick together when baked. Make sure you don't reduce or omit either ingredient, and don't stir your granola while it's baking or cooling (unless it looks like it will burn around the edges). Allow the granola to cool completely before breaking into pieces and storing.
Using quick-cook oats: Quick-cook oats are thin and cook faster than old fashioned oats, so you'll want to reduce the cooking time to 15-20 minutes.