In a large, heavy pot, warm the oil over high heat until hot but not smoking. Working in batches, brown the meat well on all sides, 5 to 7 minutes. Adjust the heat as necessary to keep the meat from scorching. Transfer the browned meat to a plate and repeat until all the meat is browned.

Add the onions and butter to the pot and stir over high heat until the onions start to soften, about 5 minutes. Reduce the heat to medium and sprinkle in the sugar. Continue to cook the onions, stirring occasionally, until golden brown, about 15 minutes. Add the flour, thyme and carrots and raise the heat to high. Stir for 1 minute, then pour in the lager or ale, letting it come to a vigorous boil. Stir in the broth and tomato paste and return to a boil.

Return the meat and any accumulated juices on the plate to the pot, let the liquid come just to a boil, then reduce the heat to low, cover, and simmer until the meat is tender when pierced and the sauce is slightly thickened, 1 1/2 to 2 hours. Season to taste with salt and pepper. Serve on warmed individual plates.