makes 2 quarts
Preheat oven to 300° F. Line one large, rimmed sheet pan (half-sheet, 13- by 18-inches) with parchment or a Silpat. In medium saucepan, melt butter with honey and maple syrup. Add vanilla and salt.
Combine oats, nuts, seeds, and coconut in a large bowl. Drizzle syrup over and mix to combine. Transfer to prepared sheet pan and spread out into an even layer. Bake for 40–60 minutes (at 300°F or 275°F with convection), moving the granola from edge to center and bottom to top a couple times during baking. The granola will crisp up as it cools. Allow to cool then store airtight.