Begin by rinsing the corned beef under cold water to remove excess brine. Cut the onion into ½-inch wedges, chop the potatoes and cabbage into 2-inch wedges, and carrots into 2-inch pieces.

In a large pot, place the rinsed corned beef along with onion wedges, pickling spice, caraway seeds, and a bay leaf. Cover with cold water, bring to a vigorous boil over medium-high heat. Once boiling, reduce heat to low, cover partially, and simmer for about 2.5 hours until tender.

Carefully remove the corned beef from the pot and let it rest covered with aluminum foil to keep warm.

Strain the broth to discard solids, return the broth to the pot, and taste to adjust seasoning.

Bring the strained broth to a simmer over medium heat, add the potatoes, and cook for about 10 minutes. Then add carrots and cabbage, simmer for 15-20 minutes.

Remove from heat, slice the rested corned beef against the grain, and serve alongside the vegetables with warm broth ladled over.