Warm oil over high heat until hot, but not smoking.  Brown meat in batches on all sides.  Transfer to a plate.

Add onion and butter to pan.  Cook till soft, about 5 minutes.  Reduce heat to medium and sprinkle in sugar.  Cook until golden, about 15 minutes, stirring occasionally.
Add flour, thyme, carrots and cook on high, stirring for one minute.  Pour in beer and bring to a vigorous boil.  Stir in broth and tomato paste and return to boil.

Return meat and juices to pot and bring to just a boil and reduce heat to low, cover, simmer until meat is tender and sauce is slightly thickened, about 1 ½ hours. Season with salt and pepper.