Position a rack in the center of your oven and heat to 325°F. Line a large rimmed baking sheet with parchment paper.

In a large bowl, toss together the oats, almonds, walnuts, pumpkin seeds, sunflower seeds, cinnamon, and salt until evenly mixed.

In a small saucepan over low heat (or in the microwave), warm the olive oil and maple syrup until loose and pourable, about 1 minute. Stir in the vanilla. This helps the granola coat evenly and clump better.

Pour the warm oil mixture over the oat mixture. Stir with a sturdy spoon or spatula until every piece looks glossy and well-coated. This takes a solid minute of stirring - don't rush it.

Spread the mixture in an even layer on the prepared baking sheet. Use the back of your spoon to press it down firmly - this creates those desirable clusters. Bake for 20 minutes.

Remove from the oven and stir gently, breaking up any large pieces that have stuck together. Press down again and return to the oven. Bake 10-15 minutes more, until the granola is deep golden and smells toasty. Watch closely - it goes from perfect to burnt quickly.

Let the granola cool completely on the pan without stirring - at least 45 minutes. It crisps as it cools. Once cool, break into clusters and stir in dried fruit if using.