In a small saucepan, melt the butter over medium heat. Continue cooking, swirling the pan occasionally, until the butter turns a deep golden brown and emits a nutty aroma. Remove from heat and let it cool slightly.
Preheat your oven to 325°F (160°C). Line a baking sheet with parchment paper for easy cleanup.
In a large mixing bowl, combine the rolled oats, chopped pistachios, coconut flakes, dried tart cherries, pepitas, ground flaxseed, and kosher salt. Stir well to combine.
In a separate bowl, whisk together the brown sugar, maple syrup, and olive oil. Add the browned butter to this mixture, stirring until well combined.
Pour the wet mixture over the dry ingredients. Stir thoroughly until everything is evenly coated.
Transfer the granola mixture to the prepared baking sheet, spreading it out evenly. Press it down gently with a spatula to ensure it clumps together as it bakes.
Bake in the preheated oven for about 25-30 minutes, stirring halfway through to ensure even toasting. Keep an eye on it; you want a nice golden color without burning.
Remove the granola from the oven and let it cool completely on the baking sheet. Once cooled, stir in the chocolate chips if using. The residual heat will slightly melt the chips, creating delicious chocolatey clumps.
Once completely cool, transfer the granola to an airtight container. It will keep for several weeks, although it’s unlikely to last that long!