1In large heavy pan, heat olive oil over medium heat. Saute onions, carrots, and celery about 10 minutes. Add beef and saute until brown on all sides.
2Add wine and thyme and bring to a boil. Add tomatoes, salt, and pepper. Reduce heat, cover, and simmer until beef is tender, stirring occasionally, about 2 hours.
3To make polenta, bring stock to a boil over medium high heat. Lower to medium. Whisk in polenta Cook and stir until it thickens, about 5 minutes. Cook inside of a bowl with olive oil. Transfer polenta to oil-coated bowl and let sit 5-10 minutes to firm.
4Remove tomato skins and thyme sprigs. Turn polenta out of the bowl, slice, and serve with beef stew.