Place the peanuts and the salt into the food processor.
Blend the peanuts until they form a fine crumb, then use a spatula or spoon to scrape the peanuts off the sides of the food processor. Keep blending and scraping down the sides until a smooth peanut butter forms.
Once the peanut butter is the consistency you like, transfer it a jar or storage container, then drizzle in the honey (if using) and stir with a spoon. Cover with an airtight lid and store in the fridge.