Preheat your oven to 325°F (163°C).

Season the brisket with salt and black pepper on all sides.

In a large Dutch oven, heat the olive oil over medium-high heat. Sear the brisket for about 4-5 minutes on each side until browned. Remove the brisket and set aside.

In the same pot, add the diced onion and cook until translucent, about 5 minutes. Add the minced garlic and cook for an additional minute until fragrant.

Pour in the beef broth and balsamic vinegar, scraping the bottom of the pot to release any browned bits.

Stir in the brown sugar and chopped sage, then return the brisket to the pot.

Add the chopped carrots, parsnips, and potatoes around the brisket.

Cover the Dutch oven with a lid and transfer it to the preheated oven. Braise for 3-4 hours, or until the brisket is tender and easily shredded with a fork.

For a thicker gravy, remove the brisket once cooked and whisk in cornstarch mixed with a little cold water. Simmer until thickened.

Slice the brisket against the grain and serve with the root vegetable gravy, garnished with fresh parsley.