Preheat oven to 400 degrees F. Prepare a casserole dish with non stick cooking stray or aluminum foil. Slice bell peppers in half lengthwise and clean out inside and place them in the prepared casserole dish.
In a mixing bowl whisk together eggs. Add diced red onion and chopped spinach. Mix together well. add 1/2 cup taco blend and salt to taste and mix again.
Pour egg mix into each bell pepper half. Top each one with remaining cheese.
Bake for 20-25 minutes or until eggs are cooked through. Time will vary so test your bell peppers by placing a butter knife or toothpick inside the eggs. You will know they are done when it can come out clean.