Mix wet ingredients: Preheat the oven to 350F. In a large mixing bowl, add the peanut butter, maple syrup, coconut oil, and vanilla extract. Use a whisk to mix until combined.

Add dry ingredients: To the same bowl, add the rolled oats, peanuts and optional salt. Use a rubber spatula or wooden spoon to stir until all the oats and peanuts are coated with the peanut butter mixture.

Bake the granola: On a rimmed baking sheet pan lined with parchment paper, spread out the oat mixture in an even flat layer. Place the sheet pan into the preheated oven for 22-25 minutes, stirring halfway through baking. Granola is done baking when it has browned and appears dry.

Serve and store: Let the granola cool completely to room temperature on the sheet pan, it will crisp up as it cools. Serve with milk, yogurt, fresh berries, on smoothies, or enjoy plain as a snack. Store in a sealed container on the counter for up to 5-7 days.