In a large skillet melt butter over medium heat. Add chopped cashews, rolled oats, and flax seeds. Cook, stirring frequently, until oats are lightly toasted, about 10 minutes. Add honey and salt and stir until evenly coated. Continue cooking until golden brown and crisp, 2-4 minutes more. Remove from heat and stir in goji berries. Spread granola on parchment paper and leave at room temperature until cool.

Once cool, granola can be stored in an airtight container at room temperature for a week.