2 hours before or up to overnight (optional doing ahead but recommended)

Cup of Yum
1. Trim excess fat from the lamb and pat dry.
2. Finely chop the garlic and mix with the olive oil, lemon juice, white wine, the salt and oregano in a medium sized bowl. Add the piece of lamb and rub the marinade all over. Cover and refrigerate for two hours or up to overnight. If you don't have time, you can also just let the lamb sit in the liquid while you prepare the vegetables and heat the oven.

When ready to cook

1. Take the lamb out of the fridge, if it has been marinating, a good 30 minutes or so before roasting. Preheat oven to 340F/170C. Place two long pieces of parchment in a roasting dish or wide Dutch oven to form a cross shape (they need to be long enough to wrap around all the lamb and vegetables.
2. Peel the potatoes and cut into large chunks of similar size if the potatoes are large. Peel and cut the onion into chunks (roughly 8 pieces) and cut the pepper into similar sized pieces. Put the potatoes at the bottom of the parchment, top with the onion, pepper and tomatoes then the lamb. Drizzle over the marinade mixture and if needed, lift the lamb to toss the vegetables in the oil mixture. Tuck the pieces of garlic in under the lamb.
3. Fold up the parchment over all of the lamb and vegetables to seal them in and bring the paper together relatively tightly. Tie with string to seal. If the parchment doesn't fully close, cover over the top with foil to seal. Place in the oven and cook for approx 2 ½ hours. Open the parchment and check the meat is tender, or else cover and return to cook a little longer.
4. Remove the meat and cover while it rests. Increase the heat to 400F/200C and trim back the paper so that the bundle is open. Return the vegetables to the oven to brown slightly on top, for around 20 minutes. Since there can be a lot of liquid/fat, you might want to either remove the potatoes to help them brown or else drain off liquid, depending what is easiest. Serve the meat and vegetables together, and a Greek salad in the side works well.