Place peanuts and flour in a food processor and whiz for about 1 minute until nuts and flour are about the same texture.
Microwave honey. This is a critical step. The honey is the liquid in the recipe. It needs to pour like water or the mix will seem dry and if too much water is added, the cookies will be tough.
Place flour-and-nut mixture in a mixing bowl and add the salt if the peanuts are not already salted. Mix in the honey and vanilla. Stir together and then mix with your hands. (If your food processor is large enough, you can mix the honey and vanilla in the processor. Turn on briefly to mix.).
Note: The dough should hold together without being dry and crumbly. If needed, add a tablespoon of water, but be careful not to get it so wet that it sticks to your hands. It should be like piecrust. If it is too dry, the cookies will crumble and not hold together, but if too wet, they will be hard to handle and the baked cookies will be hard. A little extra flour can be worked in if the dough is too sticky!
Pinch off pieces of dough and roll into balls the size of walnuts. Place on a cookie sheet and press flat with hands. Then press flatter with fork, dipping the fork in water as needed to keep it from sticking to the dough (or use a plastic fork - it won't stick even if dry, but will break unless you press on the tines).
Bake at 350 degrees F for about 10 minutes. Watch them carefully. They are done when just beginning to brown on the edges. I can think of nothing that burns so easily as peanut butter cookies, so take them out before it looks like they're done!
Let them cool on the cookie sheet before removing.