Preheat your oven to 300°. Season your brisket all over with salt and pepper. Heat a large roasting pan or dutch oven over high heat and add the oil. Place the brisket in the pot and sear the brisket for 5-8 minutes without moving it around, then flip it and do the same thing. Remove the brisket and set aside.

Reduce the heat to meduim. Add the mushrooms, onions, turnips, and garlic to the pot. Saute these for 5 minutes stirring often.

Add in the wine and 1 cup of water. Bring this to a boil while scraping off any brown bits in the pot with a wooden spoon. Simmer for 10 minutes.

Nestle in the brisket fat side up so the top 1/3 of it is above the liquid. Toss in the rosemary sprig and cover, cook for 3 hours.

Uncover and continue to cook for 1.5-2 hours. Remove from the oven, cover, and let it rest at room temp for at least 30 minutes before cutting into it or pulling it apart.

For serving, the first night we had a bed of mashed cauliflower and topped it with some brisket pieces, a few scoops of the mushroom/onion/turnip mix and some chives. Then place the leftover in the fridge to save for another dinner later in the week.