Preheat oven to 350-degrees.
In a medium mixing bowl whisk together the flour, baking soda, cinnamon, and salt. Set aside.
In a big mixing bowl, beat together the applesauce, brown sugar, yogurt, vegetable oil, egg, and vanilla with a mixer until well combined. Add flour mixture, followed by the muesli.
Drop cookie dough by teaspoon scoops onto a parchment paper-lined cookie sheet. Bake for 10 to 12 minutes.
Allow cookies to cool on pan for five minutes, then transfer to a wire rack to cool completely. Store in a sealed container between parchment or waxed paper layers; the applesauce will make the cookies slightly tacky if they touch each other. They'll keep for up to a week at room temperature.
OM NOM NOM!