Place the corned beef in a large pot. Pour the bottle of beer over the beef, and then add enough water to cover the beef; add peppercorns or spice packet. Cover the pot, bring to a boil, reduce the heat and simmer 4 hours or until tender, skimming occasionally. Remove the meat from the broth; add the carrots and onions to the broth and continue to simmer for another 45 minutes. Add the cabbage, and simmer for an additional 15 minutes.
PREPARE THE GLAZE:
Preheat oven to 400°F. In small saucepan, mix and heat glaze ingredients. Place the beef in a roasting pan and brush with the glaze. Roast for 30 minutes.
MAKE SAUCE AND SERVE:
Mix together horseradish sauce ingredients; chill until ready to use. When ready to serve, transfer the meat and vegetables to a platter; brush the vegetables with the melted butter. Serve with horseradish sauce.
Notes
The nutritional information is high (I don't think James Beard was concerned with how many calories this recipe had when he created the recipe). But take into account that ALL of the glaze and ALL of the sauce are included in the nutritional information. Same with the entire brisket, fat and all. So the calories are likely fewer than indicated.