Preheat the oven to 180C.
Toss the beef heart in the flour and shake off any excess. Heat the oil in a sauté pan and cook the onion until soft for about 2-3 minutes but not golden. Add the heart to the pan and fry until golden. Add the remaining ingredients.
Transfer the heart to an oven proof dish with a tight fitting lid. Place in the oven and cook the Ragu for 1½ -2 hours or until tender. Stir occasionally during cooking. If the sauce looks too thin, cook the Ragu with the lid off for the last half hour.
Delicious served with polenta.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.