Preheat the oven to 350ยฐ F.
Clean the leeks really well to remove all the soil. Start by cutting off the bottom, close to the roots and and removing the darkest green top part of the leeks, about 2-3 inches. Discard the roots and dark leafy ends, reserving the body of the leeks. About 6-7 inches of the leek should remain.ย Split the leeks length wise and submerge in cold water. Gently separate the leeks layers to loosen up any sand or soil caught in between, but try to keep them intact for presentation.
Once the leeks are clean, neatly lay them in a 2-quart casserole dish, seam side up. Pour in the wine and stock. Evenly sprinkle over the saffron, dabs of butter, salt and pepper. Cover and cook for 1 hour and 15 minutes.ย Remove from the oven when leeks are fork tender. Serve hot.