• Peel potatoes, cut into irregular cubes, and set aside.
• Choose a large saucepan, melt the butter in the oil, and pour in the carrot, celery, and onion. Add a pinch of salt to prevent the sauté from burning, and cook over a gentle flame for a few minutes or until the vegetables are translucent.
• Meanwhile, put some flour in a dish, flour each meat morsel, and tap lightly to remove excess flour.
• Arrange the meat bites in the pan so they do not overlap, cook for two minutes on a gentle flame, turn them over, cook for two more minutes, salt, raise the heat, wait a moment, and mix with the wine. Let the alcohol part evaporate over a gentle flame. This step takes only a few minutes.
• Pour in broth and passata and stir. Cook, without stirring, in a half-covered pan on a small stove and low flame for one hour. Stir from time to time.
• Meanwhile, dissolve the concentrate in the hot water and set aside. After an hour, add the diced potatoes, water with concentrate, passata, stir, add salt, stir again, and cook for another 30 minutes, or until the potatoes are soft, with the pan covered.
• Turn it off, taste it, and adjust the salt if needed. Serve the stew hot.

Tips

• You can prepare the dish a day or two in advance by storing it in the refrigerator and adding some warm water when you reheat it. In this way, the sauce will return soft.
• You can store the stew in the freezer for up to a month.