1Preheat the oven to 350°F. Line a baking sheet with parchment paper.
2Put the pecans and Brazil nuts in a bowl. Drizzle with maple syrup and toss to coat. Spoon onto the baking sheet, adding any maple syrup left in the bowl, and spread evenly.
3Bake for 8-10 minutes, stirring the nuts halfway through, until golden. Set aside for 10-15 minutes to cool.
4Put the maple nuts, cinnamon and salt in the blender and secure the lid. MIX for 15 seconds. Scrape down the side, then CHOP for 20-30 seconds, stopping and using the tamper to press the ingredients into the blades.
5BLEND for 15 seconds then PUREE for a further 15 seconds, scraping down the side as needed. If the nut butter is too thick, add a little oil and continue blending until a thick, spreadable consistency is reached.
6Remove the lid and scrape down the side of the blender. MILL for 30 seconds until well blended. Taste, adjust the salt to your liking.
7Spoon into a clean sterilized jar and store in the refrigerator for up to 1 month.