01 -
Preheat oven to 350°F (175°C). Grease an 8-inch pan, or line it with parchment paper.
02 -
Gently heat the peanut butter if it's stiff. Stir together the applesauce (or yogurt), peanut butter, and vanilla extract until combined.
03 -
In a separate bowl, mix the baking soda, salt, flour, sugar, and chocolate chips.
04 -
Pour the dry ingredients into the wet mixture and stir to combine. The batter will be tough to mix at first. If needed, gradually add up to 2 tablespoons of milk to achieve a cookie dough-like consistency.
05 -
Transfer the batter to the prepared pan. Spread and smooth it evenly. Optionally press some chocolate chips onto the surface.
06 -
Bake for 10 minutes. The top will look set, but the bars will remain undercooked underneath.
07 -
Let the bars cool for at least 20 minutes on a rack. They will firm up during this time and solidify more overnight.