Sear the Beef:
In a large skillet over medium-high heat, warm the ghee. While it heats, pat the beef dry and season with salt and pepper. Once the ghee is hot, add the beef in a single layer and sear each side for 2-4 minutes. Work in batches if needed to avoid crowding.Deglaze the Skillet:
Transfer the seared beef directly to the slow cooker to retain juices. After all beef is seared, reduce the heat and pour 1 cup of beef broth into the skillet to deglaze. Scrape up the browned bits, then pour the liquid into the slow cooker.Cook in Slow Cooker:
Add all remaining ingredients except arrowroot flour, water, and pearl onions to the slow cooker. Cover and cook on low for 7-8 hours or on high for 5-6 hours.Thicken Sauce with Slurry:
30 minutes before serving, whisk together arrowroot flour and water in a small bowl until smooth. Pour this slurry into the slow cooker and stir to thicken the sauce. Then add the pearl onions, stir, and cover for the final 30 minutes, until the onions are translucent and the sauce has thickened.Serve the Stew:
Serve over cauliflower mash, mashed potatoes, or enjoy as a stew on its own.