Preheat oven to 350F and line an 8" or 9" square pan with parchment paper. (Pro Tip: Grease the pan with a little spray oil first to help keep the parchment paper in place when you add the batter)
In a mixing bowl, combine the peanut butter, honey, egg, salt and baking soda and stir well, until a thick and sticky batter has formed. Fold in the dark chocolate chips, if using.
Use a spatula to pour the batter into the prepared pan, then use it to smooth the top. Sprinkle coarse sea salt over the top of the batter, if desired. (I highly recommend it!)
Bake at 350ºF until the top is a light golden brown, about 20 minutes. Let the blondies cool completely, as they are very fragile when warm, then cut into squares and serve. I like to store mine in the fridge in an airtight container, for a really firm texture and longer shelf life.