• 1 boneless corned beef brisket with seasoning packet (3-1/2 to 4 pounds)
• 6 cloves garlic, peeled
• 2 teaspoons whole black peppercorns
• 2 cups water
• 6 tablespoons butter
• 1 cup thinly sliced green onions, including white and green parts
• 1/2 cup prepared horseradish
• 1/2 teaspoon ground black pepper
• 1/4 teaspoon salt
• 1 head green cabbage, cored, cut into 6 wedges (1 to 1-1/2 pounds)
• 1-1/2 pounds small red-skinned potatoes, cut in half

Glaze

• 2 tablespoons orange marmalade
• 2 teaspoons Dijon-style mustard