Preheat oven to 350°F. Heat a deep, oven-safe pot with a lid or a large dutch oven over medium-high heat until hot.

Dredge beef in flour seasoned with salt and pepper. Shake off extra flour.

Add oil to the pot. Add the beef and sear approximately 2-3 minutes per side until all sides are golden brown.

Transfer the beef short ribs from the pot to a clean plate. Add onion, carrot and celery, reduce heat to medium and saute vegetables until soft and onion is translucent, approximately 5-6 minutes. Add garlic and stir for another minute. Add wine and continue simmering until the wine is reduced by half.

Add tomato paste, chicken stock, thyme, rosemary and bay leaf.

Return beef to pan, cover tightly and put in the oven. Cook for about two hours or until beef is tender but not falling apart.

Remove beef and strain vegetables off of sauce. Return liquid to pan and reduce until desired consistency.

Season sauce to taste.