Preheat oven to 375*F. Line a baking sheet with foil (if desired for less clean up). Add 1 teaspoon of oil to baking sheet.
Cut squash in half lengthwise. Using a spoon, carefully scoop insides out of squash. Do not discard insides -- chop them & set aside. Place squash cut side down, onto oil, and cook for 9 minutes.
Meanwhile, heat remaining 1 teaspoon of oil over medium-high heat. Add onions and peppers. Sauté for 5 minutes. Add tomatoes and leftover taco meat. Add spices and ½ cup of the reserved insides of squash. Cook for 5 more minutes.
Flip squash over to be cut side up and arrange so the squash are close together on the baking sheet. Evenly fill squash with ground beef mixture. Bake for 7 minutes.
Top each with cheese. Turn on the broiler. Broil for 1 to 2 minutes. Serve with avocado and/or cilantro if desired.
Notes
*If you don't have leftover taco meat, sauté 8 ounces of ground beef or turkey with ½ cup diced onion. Season with ½ teaspoon chili powder, ¼ teaspoon paprika, and ¼ teaspoon cumin. Drain and use in the directions where Leftover Taco Meat is called for.*Nutrition facts include avocado and cilantro.