1. Preheat the oven to 375*
2. Lightly Spray a 9x9 baking dish with nonstick spray
3. In a skillet over medium high heat, crumble and brown the ground beef, add the onions
4. Cook until the meat is no longer pink and the onions are soft
5. Drain the excess grease
6. Mix in the corn, taco seasoning and spinach
7. Stir and simmer until the Spinach has wilted
8. Slice the top portion off the tomatoes, just past the stem area.
9. Hollow out the tomatoes
10. Fill the tomatoes with the Taco meat, corn and spinach
11. Top each tomato with shredded Cheese
12. Bake for 15 minutes
13. Garnish with chopped parsley