In large bowl, beat cream cheese until smooth. Beat in sour cream, 1/4 cup of the Parmesan cheese, the milk, mustard and lemon juice until well blended. Stir in bell pepper. Chop Brussels sprouts; stir Brussels sprouts & butter sauce into cream cheese mixture until well mixed. Spread evenly in baking dish. Sprinkle with remaining 2 tablespoons Parmesan cheese.