Heat oven to 325°F (163°C). Line a large sheet pan with parchment paper.
Whisk egg whites in a large bowl until frothy and opaque, 20–30 seconds.
In another bowl, combine oats, nuts, coconut, pepitas, chia, protein powder, cinnamon, and salt.
Add oil, maple syrup, and vanilla to the egg whites. Whisk until smooth.
Stir in the dry mixture until every flake looks lightly coated. The mix should feel slightly damp, not wet.
Spread the mixture on the pan and press firmly with a spatula into an even 1/2-inch layer. Pressing creates clusters.
Bake 15 minutes. Rotate the pan. Gently break into large slabs with a spatula, then press again.
Bake another 10–15 minutes until golden and fragrant. Edges should look toasted; center should feel set.
Turn off the oven and crack the door. Let the granola cool on the pan at room temp completely—at least 45 minutes. Do not stir while cooling.
Break into clusters and fold in optional add-ins.
Paler equals softer: Want extra crisp? Bake to a deeper golden color.
Humidity hurts crunch: Cool fully before storing to avoid sogginess.
