3 to 4 lbs. corned beef brisket
1 orange, sliced
2 large onions, quartered
3 stalks celery, cut in 1-inch pieces
2 cloves garlic, quartered
1 tsp. dill seeds
3 sprigs fresh rosemary (or 1/2 tsp. dried)
6 whole cloves
1 bay leaf
3-inch stick cinnamon (or 1/2 tsp. cinnamon)
3/4 c. maple syrup
3 T. prepared mustard
1/2 tsp. coarsely ground black pepper
To make the corned beef: Coat an ovenproof baking dish with vegetable spray. Rinse corned beef under cold running water and pat dry with paper towels. Place corned beef in a large heavy pot. Add cold water to cover. Add orange slices, onion, celery, garlic, dill seeds, rosemary, cloves, bay leaf, and cinnamon. Add cold water to cover. Stir until spices are evenly distributed. Cover pot and bring to simmer over medium heat; do not boil. Simmer, covered, stirring occasionally, until a fork penetrates meat easily, approx. 3 to 4 hours (about one hour per pound of meat). Remove corned beef from pot and place, fatty side up, on prepared baking dish. Set aside.
To make the glaze: Place maple syrup, mustard and pepper in a heavy bottomed saucepan and whisk to combine. Cook over medium heat, stirring with a wooden spoon, until glaze comes to a boil. Reduce heat and continue stirring until glaze reduces and thickens, approximately 3 minutes.
Preheat oven to 375 degress. Brush half of glaze over corned beef. Bake 8 minutes. Turn corned beef fatty side down, brush with remaining glaze, and return to oven to bake 8 minutes more. Remove to a serving platter and allow to rest 10 minutes before slicing. Cut against the grain to prevent slices from falling apart. Cover leftovers with plastic wrap and store in the refrigerator.