Melt the butter in a large pot over medium, but don't let it brown.Add the mushrooms, shallot, and garlic. Cook, stirring occasionally, for about 2-3 minutes until everything is softened and fragrant. Stir in the dill, thyme, and paprika. Then add the Worcestershire sauce, white wine, and beef broth (deglaze if you need to). Adjust salt and pepper to your liking and bring the mixture to a boil.
Stir in the couscous, the cover the pot. Reduce heat to medium-low and let simmer for about 20 minutes, or until the couscous is tender but still slightly chewy (this is why pearl couscous works best).
Remove from heat and stir in the half and half until fully incorporated.
Ladle into bowls and top with a dollop of sour cream. Serve with that bread you chose. You remembered to toast it a bit, right?
