Place the nuts in food processor and process until they're finely ground, but not enough that they're beginning to turn into butter
Add the cocoa powder, almond butter, and salt. Pulse 3 or 4 times to combine.
Drain dates and squeeze out any excess water. Add the dates, one at a time through the feed tube of the food processor, while it is running.
After processing, the brownie mix should resemble cake crumbs, that when pressed, will easily stick together. Add water 1 tablespoon at a time, if desired, for moister brownies.
In a large bowl add the mix and press into a lined vessel. (I used one that was a little less than an 8 x 8" square)
Top with a few more chopped walnuts
Cover and refrigerate for at least 2 hours to set and then cut into squares
Store in the fridge in an airtight container. (They also freeze well)