First, preheat your oven to 350 F. Then add the raw walnuts to a medium baking sheet in an even layer (see below). Toast the walnuts at 350 F for 7-8 minutes. Watch very carefully when it gets to that 7-minute mark so they don’t burn, and remove from the oven immediately. Note: If using pre-toasted nuts, you can skip this step.
Carefully transfer the toasted walnuts to a food processor (they do not need to cool). Then secure the top of the food processor and start blending. This entire process of blending into a butter will take roughly 5-10 minutes, stopping periodically to scrape down the sides and re-blend as necessary. The mixture will first, form into a dry, crumbly substance, then into a thick paste, then like magic!, the natural oils from the walnuts will release and it will become more of a smooth, thick liquid. **Keep processing until you reach this smooth, liquid state.
At this point, you can remove the blade and add any of the above additions directly to the food processor OR transfer to a bowl. If you want to experiment with different flavors, try adding only a little of the walnut butter to a small bowl and add ingredients (a better option than messing up an entire batch). Or you can split the batch in two and try out two different flavor combos.
This recipe makes 1 cup walnut butter. Store it in an airtight container in the fridge for 2-3 months or in your pantry for about a month.