In a saucepan, bring the chicken stock to boil. Add tea, remove from the heat and let infuse about 15 minutes. Remove the tea bags. Set aside.
Put the grill in the center of the oven. Preheat to 350°F.
In a large ovenproof saucepan, brown the beef in butter and oil (I used a non-stick pan and used only half butter and half oil). Add salt and pepper to taste. Set aside on a plate.
In the same saucepan, brown the onions. Add more butter if needed (I didn't). Put the beef back in the saucepan and add the chicken-tea stock. Bring to boil. Cover and cook in the oven for 1 hour and 30 minutes. Add carrots and keep cooking, covered, 30 minutes. Add green beans and prunes, making sure to soak them in the stock. (that's when I added the other cup of chicken stock.) Keep cooking about 30 minutes, uncovered or until green beans are tender. Adjust seasoning.
Serve on mashed potatoes, plain couscous or noodles with butter.