Prepare cake mix according to package directions. Spoon batter into paper-lined muffin pans, filling two-thirds full.
Beat cream cheese and sugar at medium speed with an electric mixer until fluffy. Add egg, beating well; stir in chocolate morsels. Spoon 1 heaping teaspoon cream cheese mixture into center of batter.
Bake at 350° for 25 minutes. Remove from pans, and cool on wire racks. Store in refrigerator.
Note: For testing purposes only, we used Duncan Hines Swiss Chocolate Cake Mix.