Preheat oven to 350º. Spray pan cavities with vegetable pan spray.

In small bowl, combine flour, baking powder, and salt. In large bowl, beat cream cheese with electric mixer until smooth and creamy, about 3 minutes. Add butter to cream cheese and beat until creamy. Beat in sugar, egg, sour cream and vanilla. Add flour mixture into cream cheese mixture, stirring just until moistened. Gently stir in mini chocolate chips. Spoon the batter into prepared pan, filling each muffin cup 2/3 full.

Bake 8-12 minutes, or until top of muffin springs back when touched. Remove from oven and cool 5 minutes. Gently loosen the sides with a spatula and transfer to cooling grid. Cool completely before glazing.

For Glaze: In small saucepan, stir together sour cream and confectioner's sugar. Stir over medium heat until the sugar is completely dissolved. Remove from heat and stir in vanilla extract. Use immediately to glaze chocolate muffins.