1. In a shallow bowl, salt and pepper the roast lightly on all surfaces, rubbing the the meat to season well. Pour 1/2 cup of the Wine over the roast. Rub half of the rosemary, basil, garlic and onion over the TOPMOST surface of the roast and let the whole thing marinade for 15-30 minutes.
2. Carmelize the white onions in butter and olive oil. (This means to peel the onions and sear the ends and surfaces until they turn a caramel colour - brownish). OPTIONAL: You can simply use normal, white onions that are not carmalized.
3. After removing the carmelized onions from their pan, put them to one side. In the pan that was used for the carmelizing, put the remaining garlic and minced onions with some butter and olive oil. Saute the garlic and onion until translucent.
4. Add the roast, herb-side-down. (In other words, turn it over and start searing the sides of it, starting with the side that already had the first half of the rosemary, basil, garlic and onion). Sprinkle the remaining rosemary and basil over the other side as it sears. Sear each side of the roast in the pan until it is a deep, rich brown on all sides.
5. Put the roast in the bottom of a covered roasting pan and surround it with the carmelized onions, peeled whole garlic and carrots. Take the remaining juices from the marinade and pour them over the roast. Add the chicken stock.
6. Put the covered roast and vegetables into an oven at 350 degrees for about 2 hours. Your cooking time may vary with the weight of your roast. Consult a cookbook for specifics if you have a bigger or smaller leg of lamb.
7. Once the roast is done, remove it from the roasting pan and put it -with all the vegatables- on a dish for serving. (If the dish is heat-safe, put it back in the oven at a lower temperature to keep warm).
8. Put the roasting pan on the stove and add 1/4 - 1/2 cup of the Wine, bringing the liquid to a boil and loosening all the burnt and stuck bits on the side. (Basically, de-glaze the roasting pan). You may also add a cup or so of Chicken Broth. Let it boil for about 2 or 3 minutes.
9. In a separate skillet, melt a small amount of butter with some olive oil. Put the chopped mushrooms (yes, all of them) into the skillet and saute them.
10. Through a strainer, pour the de-glazed liquid over the mushrooms. Bring to a heavy boil and reduce.
11. Add 2 Tbsp. butter to the mixture and keep reducing.
12. Serve the leg of lamb with the vegetables on a platter and the gravy in a separate dish. The gravy goes well over the lamb itself and also potatos. (Irish potatos go well with this dinner.)

This recipe serves 4.