Add a splash of veg oil to a large pot on high heat. Season the meat with salt and pepper and add it to the pot. Fry the beef until it's evenly browned.

Add enough cold water to the pot to cover the meat. Put on the lid and reduce the heat to medium-low. Let simmer for 2 hours until the beef is tender. Add additional water as needed during cooking to keep the beef submerged.

Carefully transfer the meat and cooking liquid into a large bowl. Add the butter to the pot and put it back on the stove on high heat. Add the onions and fry them until they're a deep, dark brown. Watch that they don't burn and scorch the bottom of the pot. Add the brandy to the pot and deglaze 2 minutes or so until most of the brandy has cooked off.

Skim the oil from the top of the beef cooking liquid, then pour the liquid into the pot of caramelized onions. Add the stock, potatoes, mushrooms and thyme. Cover and turn the heat down to medium. Simmer 15 minutes or until the potatoes are about halfway cooked. Add the carrots. Simmer another 15 minutes until the potatoes are cooked and the carrots are tender but not mushy.

Fish the thyme from the pot. Make a slurry with the cornstarch and 1/4 cup water. Whisk it into the stew. Let simmer 5 minutes uncovered then serve with a big loaf of bread.