The duck (weighs about 5 pounds) gets scored, front and back, through skin and fat, just to the meat. Use scissors to snip through any deep fatty pockets. Pull off any wads of fat from cavity and cut off large flaps of skin that from the cavity opening as well as the back flap. Preheat oven to 300f. (I use the convection roast mode.) Bring duck to room temperature and place, breast up, in 12-inch cast iron skillet. Season all skin liberally with kosher salt, black pepper and, fresh chopped thyme (if desired). Rub seasoned skin with cut side of lemon. Roast 1 hour. Remove from oven and raise temp to 500f. While oven comes to to, carefully drain fat from skillet. Went oven reaches 500f, roast for 10 to 15 minutes- until crisp and very golden. Let rest a few, then cut into pieces and serve with giblet gravy. (Don’t throw away the fat- heaven forbid!!) strain it and freeze it.