6 tablespoons grapeseed or olive oil, plus more as needed
3 pounds beef chuck, cut into 1-inch pieces
Kosher salt and freshly ground pepper
4 carrots (1 roughly chopped, 3 cut into 1/2-inch rounds)
4 stalks celery (1 roughly chopped, 3 cut into 1/2-inch pieces)
1 onion, roughly chopped
1 tablespoon tomato paste
1 cup hearty red wine, such as shiraz
2 quarts beef stock or reduced-sodium beef broth
2 sprigs thyme
1 1/4 pounds russet potatoes, peeled and cut into 1-inch chunks
1 pound mixed mushrooms (such as cremini, chanterelle, oyster and/or stemmed shiitake), sliced or quartered if large
4 tablespoons unsalted butter
1/2 cup all-purpose flour
Chopped fresh parsley, for topping
Heat 2 tablespoons oil in a Dutch oven over medium-high heat. Season the beef with 2 teaspoons salt and 1 teaspoon pepper. Add to the pot in batches and cook, turning and adding more oil as needed, until browned all over, about 5 minutes. Transfer to a bowl with a slotted spoon.
Add 2 more tablespoons oil to the pot and reduce the heat to medium. Add the roughly chopped carrot, celery and onion and cook, occasionally stirring with a wooden spoon and scraping up the browned bits on the bottom of the pot, until the vegetables soften, about 5 minutes.
Move the vegetables to one side and add the tomato paste to the empty side. Cook until it darkens around the edge, about 2 minutes; stir into the vegetables. Add the wine and bring to a boil.
Return the beef and any juices to the pot; add the stock. Bring to a boil, skimming any foam off the top. Add the thyme. Reduce the heat to low, cover and simmer until the beef is tender, about 2 hours.
Strain the beef and vegetables in a colander set over a large bowl, reserving the cooking liquid. Tent the beef mixture with foil. Let the cooking liquid stand for 5 minutes and then skim off the fat on the surface. Return the liquid to the pot. Add the remaining carrots and celery and the potatoes and bring to a simmer over high heat. Reduce the heat to medium and simmer until the vegetables are just tender, about 20 minutes.