Preheat oven to 160°C (325°F). Line a large cookie sheet with parchment paper. Set aside.
In a food processor add soft, pitted Medjool dates, peanut butter, almond milk, oat flour, vanilla, and baking powder.
Process until a dough-like texture form - this takes a couple of minutes and you will have to stop the food processor every 30 seconds, scrape down the side of the bowl and repeat until the dough comes together. If the dough is too dry add an extra tablespoon of almond milk and process again to combine. If too wet, add an extra tablespoon of oat flour.
Add hemp seeds and pulse to combine into the cookie dough.
Using your hands, form the mixture into 12 cookie dough balls and place them on the prepared cookie sheet. They won't expand in the oven and can be close to each other on the tray.
Use your hand to press down each ball into a cookie. The thicker the chewier and softer they get.
Bake for 12-15 minutes in the center rack of the oven until golden brown.
Leave to cool on the tray for 10 minutes then cool completely on a cooling rack.
Store in a cookie jar for up to 4 days at room temperature or freeze in a sealed container.