Bring 12 cups water to a boil in an 8-quart stockpot. Add corned beef. Return to a boil and cook according to package directions.
Removed corned beef to a cutting board and cool for about 10 minutes. Slice thinly against the grain and arrange in an open roasting pan or broiler pan, overlapping slices slightly.
Preheat oven to 350 degrees. Combine brown sugar, mustard, and ketchup in a small bowl. Mix well. Spread evenly on top or and between corned beef slices. Bake, uncovered, for 20 minutes or until glaze is browned.
Heat oil in stockpot set over medium-high heat. Add cabbage and sugar. Cook, stirring frequently with a long-handled spoon, until crisp tender, 10 to 12 minutes. Arrange cabbage on a serving platter. Top with corned beef.
Serve with Green Giant Roasted Potatoes Vegetable Steamers for a side dish ready in minutes.