Place potatoes, carrots and celery into the insert of your slow cooker. In a large pan, brown the meat on all sides. Transfer me to the crockpot
In the same pan, sauté the onion until tender. Add garlic: cook 1 minute longer. Combine the flour, sugar, brown sugar, seasonings, orange peel and cocoa. Stir in tomato sauce; add to the pan and heat through and pour over the beef.
Cover and cook on low for 6 to 8 hours or until the beef and vegetables are tender