Pre-heat the oven to 400 degrees. Spray a 12-cup muffin time lightly with oil spray and fill each cup with muffin liners. Place rolled oats in the bowl of a food processor and process until it is fine, 45-50 seconds. Add in the almond flour, buckwheat flour, arrowroot powder, baking powder, baking soda, cinnamon and salt. Pulse 6-7 times to make sure that they are completely mixed. Transfer the dry ingredients into a large mixing bowl. Wipe the bowl of the food processor with a paper towel. Do not wash. Place the dates, yogurt, coconut oil, eggs, and 1/3 cup of the applesauce in the bowl of your food processor. Process until smooth, 40-50 seconds. You may have to stop the food processor and scrape the bottom of the bowl a few times to ensure that the dates are not sticking to each other. Gently fold in the wet ingredients into the dry ingredients. Grate 2 of the apples and fold them (with their juices) into the batter. Slice the third apple thinly and set aside. Drop a heaping tablespoon of the muffin batter into each muffin tin. Divide the rest of the reserved applesauce amongst 12 muffin tins (each should be around 1-teaspoon applesauce). Cover each muffin tin with the rest of the batter. Top each muffin batter with 3 thin slices of apple like you see in the images. Gently press them down. Sprinkle each muffin with a little bit of cinnamon. Bake for 20-22 minutes. Let them cool for at least an hour before serving.