Preheat oven to 400°F.
Combine flour, baking soda, salt, and cinnamon in a large bowl. In a separate bowl, whisk together egg, honey or maple syrup, coconut oil, applesauce, vanilla, and lemon zest (if using). Pour wet ingredients into dry ingredients and stir until combined. Fold in oats and blueberries.
Spoon onto a cookie sheet greased with coconut oil. Bake for 14 minutes, rotating pan halfway if necessary. Enjoy!