Melt butter in small saucepan on medium heat. Stir in Sauce Mix. Gradually stir in milk. Bring to boil, stirring constantly. Reduce heat to low; simmer 1 minute or until thickened, stirring constantly.
Stir in spinach, pimientos, Parmesan cheese and dill. Cook until cheese is melted and sauce is well blended, stirring frequently. Remove from heat. Add sour cream; stir until smooth.