Bring water and salt to a boil. Add buckwheat groats, amaranth and chia. Cover, reduce heat and simmer for 10-15 minutes, stirring occasionally, until mixture is creamy and all water is absorbed.
Meanwhile, in a non-stick skillet, cook onion, salt and pepper over medium heat until translucent. Lower heat, add spinach and stir until spinach is completely wilted, about 1 minute. Turn off the heat and set aside.
In a mixing bowl, combine cottage cheese, sharp cheddar and nutmeg.
Fold in spinach mixture and toasted walnuts. Mix until well combined.
Divide buckwheat mixture between 2 oven safe dishes and spread evenly.
Top with spinach and cheese mixture, make a little well to accommodate the egg.
Crack the eggs in the little well, sprinkle with salt and bake in the oven for about 15-20 minutes or until the egg has set.