Preheat oven to 170F and line a baking sheet with parchment or a silicon baking mat.
In a large bowl, mix together the almonds, cashews, and maple syrup. Spread the nut mixture out onto the prepared baking sheet and bake for 40 minutes, stirring once half way through.
Remove from oven and allow to cool.
Place roasted nuts and oil into the bowl of your food processor and process until drippy, scraping the bowl as needed. This should take between 6-8 minutes.
Recipe by Healthful Pursuit at https://www.healthfulpursuit.com/2011/04/maple-mystery-butter/