In a large bowl, whisk together the oats, flour, baking powder, cinnamon, and salt.
In a medium bowl, combine the applesauce, butter, egg, vanilla, and honey. Whisk until blended. Pour the liquid mixture into the flour mixture and stir just until combined. The dough should be wet and sticky. Place in the refrigerator and let chill for about 30 minutes.
When ready to bake, place a rack in the center of your oven and preheat the oven to 350 degrees F. Line a large rimmed baking sheet with parchment paper or a silicone baking sheet. Remove the dough from the refrigerator (if it is very stiff, you may need to let it sit out for 5 to 10 minutes). With a cookie scoop or spoon, drop the dough into 1 1/2-inch balls and arrange on the baking sheet, leaving 1 inch of space around each. Gently flatten each cookie to be about 3/4-inch thick.
Bake for 8-10 minutes or until golden. Let cool on a wire rack.