Cut the tops off the bell peppers and remove the seeds and membranes. Brush the outer sides lightly with olive oil and place them upright in a baking dish.
In a skillet over medium heat, add olive oil and sauté the diced onion until translucent, about 3-4 minutes.
Add minced garlic and ground turkey (or chicken) to the skillet, cooking until the meat is browned and cooked through, approximately 7-10 minutes.
Stir in the cauliflower rice, taco seasoning, salt, and pepper; cook for another 2-3 minutes until well combined.
Remove the skillet from heat and stir in half of the shredded cheese, mixing well.
Stuff each bell pepper generously with the turkey mixture, pressing down gently to pack it in.
Sprinkle the remaining cheese evenly on top of the stuffed peppers.
Cover the baking dish with aluminum foil and bake for 25 minutes. After 25 minutes, remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden.
Remove from oven and let cool slightly. Garnish with fresh cilantro before serving.