Preheat the oven to 400 degrees F. Cut the bell peppers in half and remove the seeds. Place the pepper halves, cut side up, in a rimmed baking dish.
Set a large skillet over medium heat. Add the butter and onions. Sauté for 2-3 minutes to soften. Then add in the ground beef. Break the meat apart with a wooden spoon and brown for 4-5 minutes.
Mix in the taco seasoning, rotel, and 1 ¼ cups shredded cheese. Stir well. Scoop the meat filling into the empty bell pepper halves.
Cover the dish with foil and bake for 30 minutes, or until the peppers are soft. Remove the foil the last 5 minutes, and sprinkle the remaining cheese over the tops.
Serve warm, as-is, or topped with sour cream, pico de gallo, cilantro, lime wedges, or shredded lettuce.
Don't want to use ground beef?You can use ground turkey, chicken, or pork as well!Place cooled leftovers in a container with a lid and keep in the refrigerator for up to 4 days. Enjoy the stuffed peppers cold, or reheated in a microwave or oven.I do not recommend that you freeze, however, as the peppers tend to get a bit mushy after thawing.