Sear meat: Pat meat dry with paper towels, then season on all sides with salt and pepper. Heat a Dutch oven over high heat for 2 minutes. Then add enough oil to barely coat bottom of pot and heat until shimmering. Sear the meat until golden brown, turning to cook all sides evenly, about 8 minutes.

Cook aromatics: Reduce heat to medium. Add the olive oil and all of the aromatics, and cook, stirring fairly often, until the onion is translucent, 2 to 3 minutes.

Add flour: Sprinkle the flour into the pot, and stir to coat everything evenly; cook the flour just long enough to remove the starchy taste without taking on any color, about 30 seconds.

Add vinegar and deglaze pot: Add vinegar and water, and bring to a boil. Deglaze pot, scraping up browned bits from the bottom.

Return roast to pot: Put the roast in the pot; the water should come only about 1 inch up the sides of the meat. Reduce the heat so the liquid is simmering, not boiling, and cover the pot tightly with the lid so meat braises. Turn the meat every 30 minutes; the meat should be almost tender (a sharp knife inserted in the center should meet little resistance) after 2 ½ to 3 hours.

Remove meat, strain liquid: Remove the meat from the pot. Strain braising liquid through a fine sieve, pressing on the solids to extract as much liquid as possible (discard solids).

Place meat and liquid back in pot; add garnish vegetables: Return the roast and the strained liquid to the pot. Nestle the garnish vegetables around the roast, submerging them a bit in the liquid (the liquid should almost reach top of vegetables). Bring the liquid to a boil, then simmer until the vegetables are tender, 15 to 20 minutes.

Let meat and vegetables rest: Transfer the meat and vegetables to a serving platter, let stand for 15-20 minutes.

Keep sauce warm, adjust consistency or flavor if needed: There should be about 1 cup of sauce in the pot. Cover pot to keep it warm while meat rests. If the sauce is too thin, heat until reduced (but be mindful of the saltiness, since the more sauce is reduced the saltier it will taste) or thicken it with a bit more flour, whisking until smooth. Add a small amount of vinegar if necessary to balance the flavors.

Serve pot roast with vegetables and sauce: Remove trussing string and slice roast to desired thickness. Spoon some sauce over meat and vegetables to moisten and serve with remaining sauce on the side.