In 2-quart mixing bowl, whisk flour and beef broth together until any lumps are gone.
Spray pot or Dutch oven (6-quart) with oil and place on medium-high heat. When pot is heated, brown beef in three batches, adding more spray for each batch. Do not overcrowd pot; its bottom should be visible.
Spray a nonstick pan with oil and heat on medium high. Add onions and cook, stirring occasionally, until brown and soft. Remove from pan and reserve; repeat with carrots, cooking until browned.
Once beef is browned, add mushrooms to Dutch oven and cook for 1 minute. Add wine; cook until reduced by half, about 3 minutes.
Return browned beef to Dutch oven; add caramelized onions and carrots, as well as celery, garlic, tomato paste, thyme leaves, bay leaves and ground pepper. Stir in flour and beef stock mixture.
Bring pot to a simmer, then reduce to low heat and cook for 45 minutes, or up to 2 hours if time permits. (The longer the stew simmers, the more tender the beef will become.) While stew is simmering, occasionally check it and skim any excess fat from the top.
Bring 4 quarts water to a simmer in large pot. Place cauliflower florets in simmering water and cook 8 minutes or until tender. Drain and keep cauliflower warm.
Remove stew from heat and stir in lemon juice. Divide cauliflower equally among 8 bowls, then ladle stew over cauliflower.
(Optional: Garnish each bowl with a dollop of sour cream and sprinkle with small pinch of fleur de sel)
Recipe by Views From the Ville at http://viewsfromtheville.com/2014/02/14/angus-beef-stew-recipe-rehab/