Preheat oven to 325°F (165°C) and line a rimmed baking sheet with parchment paper.
In a large mixing bowl, combine the rolled oats, chopped peanuts, cinnamon, and sea salt.
In a separate microwave-safe bowl or small saucepan, whisk together the peanut butter, maple syrup, and coconut oil until smooth. Stir in the vanilla extract.
Pour the liquid mixture over the dry ingredients and stir with a spatula until the oats are uniformly coated.
Spread the granola in an even layer on the prepared baking sheet, pressing down slightly with the back of a spoon to encourage cluster formation.
Bake for 22 to 25 minutes, rotating the pan halfway through. Do not stir if large clusters are desired.
Remove from the oven when the edges are golden brown. Allow the granola to cool completely on the pan for at least 45 minutes to reach final crispness before breaking into pieces.