Place cauliflower in a steamer basket; place in a small saucepan over 1 in. of water. Bring to a boil; cover and steam for 4-5 minutes or until crisp-tender. , Meanwhile, in another small saucepan, melt butter. Stir in flour until smooth. Remove from the heat; stir in the sour cream, Parmesan cheese, salt and pepper. , Add cauliflower to the cream sauce. Cook and stir over low heat for 1-2 minutes or until heated through. Sprinkle with parsley if desired.