Begin by neatly trimming the tops off the bell peppers, and set aside. You may also need to slightly trim the bottoms of the peppers so that they can stand on their own. Remove the seeds and pull out the white veins.
In a mixing bowl combine eggs, ricotta, herbs, garlic powder, salt and pepper. Mix well and set aside.
In a pan over medium-high heat, sautee in a little olive oil the onion and sausage until the onion is translucent and sausage slightly browned, then add the spinach (add a little salt and pepper) and cook until wilted. Remove from heat and add one spoonful from the pan into the mixing bowl, and stir immediately (we are tempering the ricotta/egg mixture so that the eggs don't scramble.) Continue spoon-by-spoon for about half the pan, and then add the rest and mix well.
Spoon the cheese mixture evenly into the hollowed bell peppers, and place onto a nonstick baking sheet.
Place the baking sheet into your 400 degree oven. Try putting the tops next to each pepper in the oven, and just monitor them so they don't over-brown. Bake for 30-40 minutes until the cheese on top is bubbly.