Slow Roasted Glazed Pork Shoulder

Crush fennel seeds and peppercorns with the bottom of a heavy skillet, or use a mortar and pestle. Transfer spices to a small bowl; add 1/4 cup salt and sugar. Rub mixture all over shoulder. Place in large glass baking dish, cover, and refrigerate for at least 6 hours or preferably overnight.
Preheat oven to 325. Brush off spice rub from meat and place pork in a deep roasting pan; discard excess spice rub and any liquid in dish. Add 1 cup boiling water to roasting pan; cover pan tightly with foil (Create a tight seal to lock in the steam and juices.)
Transfer pan to oven and roast until meat is very tender and falling off the bone (an instant read thermometer inserted into the center w/o touching the bone will read 195), about 5-1/2 hours.
Remove pan from oven; discard foil. Increase heat to 500. Stir in 1/4 cup vinegar, brown sugar and cinnamon into pan juices. Return to oven and roast, watching closely to prevent burning, until pork is browned and liquid begins to reduce, about 12 minutes.
Transfer pork to rimmed baking sheet, set aside. Pour liquid in pan into a small saucepan. Bring liquid to a boil and cook, occasionally spooning off fat until a thick, syrupy glaze forms, about 10 minutes (there will be about 1-1/2 cups glaze and 1 cup of fat; discard fat). Season glaze with salt and pepper. Slice pork, pour glaze over.