Heat oven to 350°F. Line 24 regular-size muffin cups with paper baking cups. In medium bowl, beat 1/2 cup sugar and the cream cheese with electric mixer on medium speed until smooth. Beat in egg. Stir in chocolate chips; set aside.
In large bowl, beat remaining ingredients on low speed 30 seconds, scraping bowl occasionally. Beat on high speed 3 minutes, scraping bowl occasionally. Reserve 1 1/2 cups batter.
Fill each muffin cup one-third full (1 rounded tablespoon) with batter. Spoon 1 tablespoon cream cheese mixture onto batter in each cup. Top each with reserved batter (1/2 rounded tablespoon).
Bake 30 to 35 minutes or until toothpick inserted in center comes out clean. Store in refrigerator.