Prep onions, carrots, and mushrooms are explained above.
In a large dutch oven (heavy ovenproof pot), add olive oil and heat till hot
Brown onions. Remove from pot and set aside.
Brown carrots. Remove from pot and set aside.
Brown mushrooms. Remove from pot and set aside.
While veggies are browning, mix flour, salt & pepper together in flat dish and thoroughly coat all side of chuck roast (dredge) with flour mixture. Save extra for thickening gravy if desired.
Add additional oil if necessary to hot pan and brown all sides of chuck roast.
Remove roast and set aside.
Add about one cup of the beef stock to pot and stir and scrape brown bit from bottom.
Add meat back into pot. Add in carrots, onions, and mushrooms. Add remaining broth (enough to cover meat 1/2-3/4 of the way). Add sprigs of rosemary and thyme.
Place covered pot into 350• oven and cook for 1/2 hour. Reduce heat to 275• and continue to cook for approx. 4 hours. Cooking times might vary slightly depending on size of roast. It's done when meat begins to fall apart and veggies are really tender.
Remove meat and veggies from pot and thicken gravy on stovetop with flour mixture if desired (combine a few tablespoons of flour with 2 TBL water till smooth and stir into cooking liquid over high heat).
Serve with mashed potatoes.