Heat the oil over medium heat in a large skillet. Add the onions and garlic and cook slowly, stirring occasionally, until caramelized and golden, about 30 minutes.
Move the onions to the sides of the pan and add the chicken to the center in a single layer. Sprinkle the chicken with the salt and pepper. Cook for 4-5 minutes on each side or until 155 degrees with a meat thermometer.
Top the chicken with the cooked onions and bouillon or soup mix if using. Sprinkle on the cheese. Place the pan under the broiler for 2-3 minutes until the cheese is golden brown and the chicken has reached 160. Serve immediately.
Nutrition: this recipe has 6 servings. Each serving has 5 NET carbs.Substitutions: you are welcome to use any kind of cheese that you like. Beef Bouillon or Onion Soup Mix: this is optional but really does boost the flavor and make this taste more like French onion soup. If you choose not to use it you make want to add a little more salt to taste when serving.To Reheat: warm in the microwave for 1 - 2 minutes or until you see that it’s hot. Or you can warm it on the stovetop slowly in a covered skillet. Use low heat and only warm it until it’s hot. To Freeze: after it’s cooled, add the chicken to a freezer bag filling it ⅔ full, or put it into an airtight container. Freeze for up to 2 months—Thaw in the fridge and reheat before serving.