Preheat your oven to 350°F (175°C). Rinse the corned beef brisket under cold water to remove excess salt, then pat it dry with paper towels.

In a large Dutch oven, add the quartered onions, smashed garlic, and bay leaves. Place the rinsed corned beef brisket fat side up atop the aromatic layer. Pour in the dark beer or beef broth until it reaches halfway up the brisket, sprinkle with salt and pepper, and add fresh herbs if desired.

Cover the Dutch oven with its lid and bake for 1 hour at 350°F, then reduce the heat to 300°F (150°C) and cook for an additional 2 hours.

Carefully remove the lid and add the chopped carrots and halved baby potatoes, stirring them into the broth. Cover again and continue to cook for one more hour.

Add the cabbage wedges during the last 30 minutes of cooking, keeping the lid on to trap moisture.

After a total of 2 hours with the vegetables and 30 minutes with the cabbage, check the corned beef for doneness; it should shred easily with a fork. Let it rest for 10-15 minutes.

Using a slotted spoon, transfer the vegetables to a serving dish. Slice the corned beef thinly against the grain and serve it alongside the vegetables.