I like the natural sweetener Truvia, which is made from the stevia plant. If you use granulated sugar instead, use 2 tbsp.
First, grind up the walnuts. I used this pyrex measuring cup and the thick wooden handle of a spoon as a makeshift mortar & pestle. Electric grinders work fine as well of course.
Measure out your muesli. I happen to like this brand, but you can buy another kind or better yet - make your own mix.
Measure out and add everything, except for the egg, to a medium mixing bowl.
Off to the side, in a small bowl, whisk your egg.
Add the egg to your mixture.
Stir with a medium spoon until it's mixed well.
Get your baking pan ready.
Preheat your oven (I used a convection oven) to 400 degrees Fahrenheit.
Fill each of the six paper baking cups half full with your mixture and make sure they're all the same size (as best you can)
Bake at 400 degrees Fahrenheit for 15 minutes, until the tops are golden-brown.
Nutrition facts for the particular ingredients I used. Serving: 1 cookie