Flourless Peanut Butter Chocolate Chunk Squares are quick an easy to make, but they do taste best after they've cooled. For best results, use unsweetened peanut butter. I used Trader Joe's unsweetened.
Preheat oven to 350°F. Line inside of a 9 ½ by 5 ½ inch loaf pan with nonstick foil.
With a hand-held mixer, beat the egg, brown sugar, salt, baking soda and vanilla in a bowl until well blended and sort of foamy (about a minute). Add the peanut butter and beat until blended, then stir in the chocolate chips and nuts.
Scrape into the loaf pan and smooth to make an even layer.
Bake for 20-25 minutes or until bars appear set. Let cool completely, then lift from pan and if desired, put the bars in the refrigerator for a few hours to chill (this makes them chewier). Cut into squares.