Preheat Oven 375°F. Line 10" x 15" baking tray with parchment paper.
Whisk butter, apple sauce, sugar and vanilla until light and creamy. Then add egg and whisk again.
Mix flour, baking soda, and salt seperately. Then stir into batter.
Spread across try with 1" space from edge of tray. Then sprinkle chocolate chips on top.
Bake 10-15 mins. Cool for 10- 20 mins. Cut 1/2" strips.