Preheat oven to 350°F (175°C). Line a sheet with parchment paper.
Whisk oats, flour, baking soda, cinnamon, and salt in a bowl.
Mix applesauce, oil, syrup, egg, and vanilla in another bowl.
Stir until the wet mixture is fully emulsified.
Incorporate wet ingredients into dry ingredients. Stir until just combined.
Fold in the dark chocolate chips gently.
Scoop rounded tablespoons of dough onto the baking sheet.
Flatten each cookie slightly with the back of a spoon.
Bake for 10 to 12 minutes until edges are golden.
Cool on the sheet for 5 minutes. Move to a rack.