Preheat oven to 375°.
Combine the cream cheese and preserves; stir with a whisk.
Lightly spoon flour into dry measuring cups; level with a knife. Combine flour and the next 5 ingredients (flour through salt) in a medium bowl; make a well in center of mixture. Combine buttermilk, oil, egg whites, and egg; stir well with a whisk. Add to flour mixture, stirring just until moist.
Spoon the batter into 12 muffin cups coated with cooking spray, filling one-third full. Top each with about 1 teaspoon cream cheese mixture; divide the remaining batter evenly over the cream cheese mixture. Bake at 375° for 25 minutes or until muffins spring back when touched lightly in center. Remove the muffins from pans immediately, and place on a wire rack.