Bake the potatoes until tender, 45 minutes to 1 hour. Allow to cool, and then peel and grate them. Season well with salt and pepper.
Adjust the oven temperature to 450 degrees F. Spray two 12-hole muffin pans generously with cooking spray. Scoop 3 to 4 tablespoons of grated potato into each muffin hole. Use your fingers to gently press down the sides and bottom in each muffin hole to make a nest. Spray again with cooking spray. Then bake for 15 to 20 minutes. Watch and make sure they do not burn.
Allow the nests to cool and lower the oven temperature to 400 degrees F. Then crack an egg into each nest. Sprinkle with salt and pepper and bake until the whites are set, about 15 minutes.