Preheat oven to 350 degrees F and spray 12 muffin cups with nonstick cooking spray. Wash and dice strawberries. In a large bowl fit with a mixer, combine flour, sugar, baking powder, baking soda and salt and whisk together. In a separate bowl, combine applesauce, milk, egg and vanilla extract and whisk well to combine. Pour liquid mixture slowly into flour mixture and beat on medium-low just until combined. Batter may be very liquid, this is normal. Stir in diced strawberries and chocolate chips. Pour batter 4/5 up to the top of muffin tin, making sure to scoop chocolate chips from the bottom.