Place brisket in a large stockpot. Cover with water and add seasoning packet.
Bring pot to a boil, then simmer for about 3 hours until meat is tender. Reserve 2 tablespoons of the cooking liquid for the glaze. When meat is done, remove from the pot and discard the cooking liquid.
In a small saucepan, combine orange juice, brown sugar, corned beef juice, mustard, and bourbon.
Whisk in cornstarch until smooth. Bring to a boil and cook until glaze has thickened, about 1-2 minutes.
Preheat the oven to 350 degrees.
Arrange vegetables in a single layer on a roasting pan. Drizzle with olive oil. Sprinkle with salt and pepper.
Place the corned beef in the roasting pan on top of the vegetables. Apply glaze liberally over the top of the entire corned beef.
Place corned beef and vegetables in the oven. Glaze the corned beef every 10 minutes for 30 minutes .
Remove the corned beef from the oven and set on the counter to rest for 15 minutes.
Turn on the broiler and continue to roast the vegetables until they start to brown, about 5-10 minutes.
Slice the corned beef against the grain. Serve over roasted vegetables. Drizzle with the glaze.