Preheat the oven to 350 degrees F and grease a 12-cup muffin pan.
In a large bowl, whisk together the egg whites, maple syrup, cinnamon, and salt until frothy. (You can do this with a dinner fork–just whisk for a good minute or two.)
Add the remaining ingredients and stir until fully incorporated.
Divide the mixture evenly among the muffin cups. Press down firmly with the flat part of a small measuring cup to compact the ingredients.
Bake for 15 minutes (give or take a couple of minutes depending on oven) or until the rounds appear dry in the center and lightly golden around the edges. Let cool in the pan for 10 minutes, and then pop the rounds out of the pan using the tip of a dinner knife.
Serve warm or cool completely and store in an airtight container at room temperature for up to 3 days. They will be chewiest the day they are cooked and will become slightly crisper over time.