4 to 5large Russet potatoes,about 3 pounds, peeled and quartered
2large sweet bell peppers,cored and cut into large chunks (I used red and orange sweet peppers)
2large tomatoes,cut into thick wedges
1large red onion,cut into large chunks
½cupvegetable or beef broth
4ouncesfeta cheese,cut into blocks, optional
Season and marinate the lamb. Place the boneless leg of lamb in a large bowl. Using a sharp knife, make a few slits in the boneless leg of lamb. Rub the lamb all over with 2 tablespoons dried oregano and ½ tablespoon each dried thyme and dried parsley. Season well with kosher salt and black pepper on all sides. Then rub with the mustard and the majority of the garlic (reserving 1 tablespoon of the garlic for the vegetables). It’s important to push some of the garlic and seasoning into the slits you’ve cut earlier for best flavor. Transfer the lamb to a large bowl and add the lemon juice, red wine vinegar, white wine and about ¼ cup of extra virgin olive oil, turning the lamb in the bowl to make sure it is well coated. Set the lamb aside for a few minutes while working on the vegetables. (But if you do have the time, cover the bowl and refrigerate for a couple hours or up to one night).
Preheat the oven to 375°F. And position a rack in the middle.
Prepare the roasting pan and parchment paper. Line a large roasting pan with two very large pieces of parchment paper, making a cross shape so that you have long pieces of parchment overhang on all sides of the pan (I like to have about 8 inches of parchment overhang on all sides of the pan).
Assemble the vegetables and lamb in the pan. Spread the potatoes, bell peppers, tomatoes, and onions in the bottom of the pan over the parchment. Season with a good pinch of kosher salt and black pepper and the remainder of the dried oregano, thyme, and parsley. Sprinkle the remainder of the garlic on top and drizzle with a little olive oil. Add the lamb on top of the vegetables and pour the broth in from the side of the pan.
Fold the parchment to cover the lamb and vegetables. Pull parchment paper sides together and tightly crimp them up to fully encase the lamb and vegetables in the parchment parcel.
Roast. Place the roasting pan on the center rack of your heated oven and cook for about 3 ½ to 4 ½ hours or until the meat is tender and falls apart easily at the touch of your fork (you can check partway through and add more broth or water, if needed).
Brown. Uncover the meat and veggies and fold excess parchment paper into the inside of the pan. If using, add the feta cheese at this point. Raise the heat to 425°F and return the pan to the oven (uncovered) for a few more minutes until the lamb and vegetables gain some color (about 15 to 20 minutes) to 425°F to allow the meat and veggies to brown).
Let rest. Once ready, allow the lamb kleftiko to sit for about 20 to 30 minutes before serving.
Serve. Pull the meat apart using two forks to shred. Serve the lamb in bowls over the vegetables!
To work ahead and for best flavor, marinate the lamb in the fridge for a couple of hours or up to one night in advance. Bring it closer to room temperature before cooking.