Process the oats, flaxseeds, peanut butter, vanilla powder, salt (if using), and maple syrup in a strong food processor. Everything will start off very crumbly, but then it should start to come together a bit. Scrape down the sides as needed.
When everything is well pulsed, try to pinch a bit of the mixture together and see if it holds together. If it is too crumbly, add in a bit of water about ½ a tablespoon at a time. Different peanut butter brands vary, which affects how much water you need, if any.
Roll into balls about 1 tablespoon in size. Store covered in the refrigerator. You may need to separate layers with parchment paper.
Notes
Vanilla powder is expensive, but it's worth it especially for no cook recipes. It's pure ground vanilla beans, without the ethanol or any other ingredients typically added into vanilla extracts.Because different brands of peanut butter vary in consistency, you may need to make slight adjustments to the exact amount of peanut butter, maple syrup, and oats that you use.