Preheat your oven to 350°F (175°C).
Grease an 8x8 inch baking pan or line it with parchment paper.
In a large mixing bowl, combine the applesauce or yogurt, peanut butter, and vanilla extract until smooth.
Add baking soda, salt, and flour to the wet mixture and stir until just combined.
Gradually mix in the granulated sugar. If thick, add milk to reach desired consistency.
Fold in chocolate chips until evenly distributed.
Pour the batter into the prepared baking pan and bake for 20-25 minutes.
Cool in the pan for 10-15 minutes before transferring to a wire rack to cool completely.