A combination of ¾ cup almonds and ½ cup cashews also works well, and I have also made these with only almonds and they still work beautifully ‐ you just need to be sure to process the almonds long enough to become fine/powdery before moving on with dates, etc.
You can substitute 1 – 1 ½ tsp of pure vanilla extract for the vanilla bean seeds.
If your dates are on the dry side, you can add 1‐2 tbsp of water to the mixture to help assist the pureeing and the mixture easily coming together.
If you process the mixture too long, the heat generated by the food processor will bring the oils out of the nuts. If this happens, the brownies won’t be ruined necessarily, but they will have an oily appearance and be oily to the touch. So, process minimally to begin, rather than over processing the nuts at the outset.