Preheat the oven to 350 degrees F. Line a baking sheet with parchment paper.
Soak the dates in a bowl of boiling hot water for 5 minutes to soften.
Add the dates, applesauce and cinnamon (if using) to a food processor and blend until very smooth, scraping down the sides occasionally. Next, add in 1 1/2 cups of the large flake oats and run for about 4-5 seconds, or just until the oats are roughly chopped up.
Remove the blade of the food processor, and fold in the remaining half cup of oats until evenly distributed. You can also transfer to a bowl if your food processor is small.
Using a large spoon, form 12 mounds of the oat cookie mixture and place on baking sheet about 1-inch apart. Do not press down on the mixture, but instead leave it in mounds on the baking sheet.
Bake for 10 minutes. Rotate the pan and bake for an additional 7 to 9 minutes, or until cookies are slightly firm to the touch and lightly golden on top. Allow to cool for several minutes on the baking sheet before transferring to a cooling rack. Cool fully before serving.