Broccoli or romanesco with mustard sauce

Makes 4 servings
1/2 cup chicken broth
1/2 tsp. dried thyme
3 cups broccoli or romanesco florets
2 Tbsp. sour cream
2 tsp. flour
2 tsp. Dijon mustard
1.  Bring broth and thyme to a boil over high heat.  Add broccoli or romanesco.  Return to a boil.
2.  Reduce heat, cover and simmer 5 minutes, or until tender-crisp.  Retain cooking liquid, and remove broccoli;  keep warm.
3.  Blend sour cream, flour, and mustard.  Stir into cooking liquid still in saucepan.  Cook and stir over medium heat until thickened, about 2 minutes;  cook and stir 1 minute more, but do not boil.  (If sauce is too thick, add more broth, 1 Tbsp. at a time)
4.  Return broccoli to saucepan with sauce.  Stir gently until coated.  Serve at once.