Heat the ghee or bacon fat in a large skillet and saute the onion, carrots, and celery until tender, 5 to 7 minutes.
Add the garlic and cook until fragrant, about 30 seconds.
Stir in the salt, pepper, red pepper, oregano, and thyme. Add the tomato paste and stir to coat, cooking 2 or 3 minutes. Stir in the nutmeg and add the mix to the slow cooker.
Brown the ground beef in the now empty skillet. Add to the slow cooker.
Add the cooked bacon or pancetta, coconut milk (with arrowroot powder stirred in if needed to thicken), strained fire roasted diced tomatoes, and the bay leaf to the slow cooker. Stir all to combine.
Cover and cook on low for to 7 hours. For the last half hour, remove the lid and allow the sauce to thicken.
Serve over oven-roasted spaghetti squash or (break those paleo rules) polenta, or thick pasta.