Preheat oven to 225°F. Line a baking sheet with parchment paper.
Combine oats, almonds, coconut, cinnamon, and salt in a large bowl. (Coconut is optional)
Beat egg whites in a glass, metal, or ceramic bowl until stiff peaks form. Beat in vanilla extract. Fold sugar into egg whites. Fold egg whites into the oat mixture. Spread on the prepared baking sheet.
Bake in the preheated oven, stirring every 20 minutes, until granola is crispy, about 1 hour.
Let cool on counter. When cool, put in airtight container (I use a glass mason jar).