Preparation

1. Make the pot roast: Preheat the oven to 150°C. Season the beef all over with 1 tablespoon of salt. Heat 2 tablespoons of the oil in a HexClad 4.7 Litre Casserole Dish over high heat for 2 minutes. Add the beef and cook, turning a few times, until golden brown all over, about 12 minutes. Remove the beef to a plate.
2. Drain excess oil and wipe any blackened bits from the bottom of the Casserole Dish with a paper towel. Return to medium heat and add the remaining tablespoon of oil, onion, the carrots cut into 2.5 cm pieces, and celery. Cook, stirring occasionally, until the onion is translucent, about 3 minutes. Add the garlic and cook, stirring, until fragrant, about 1 minute more.
3. Sprinkle the flour into the Casserole Dish and cook, stirring, until lightly toasted, about 1 minute. Return the beef and any accumulated juices to the Casserole Dish and add the wine, stock, thyme, rosemary, and 2 teaspoons of black pepper. Increase the heat to high and bring to a rolling boil. Cover and transfer to the oven. Bake until the beef is fork-tender, about 2½ hours.
4. Meanwhile, make the pickled onion: In a HexClad 2 Litre Hybrid Saucepan, bring the vinegar, sugar, 2 teaspoons of kosher salt, and 120ml of water to a boil, stirring until the solids dissolve. Remove from heat and stir in the onion. Let sit at room temperature for 1 hour, then cover and refrigerate until ready to use.
5. Remove the beef from the Casserole Dish to a work surface and tent with foil. Set a fine sieve over a large heatproof bowl and carefully strain the liquid into the bowl, pressing on the solids to extract as much liquid as possible; discard the solids.