Heat oven to 400°F. Spray 12 muffin cups with nonstick cooking spray, or line muffin cups with paper baking cups and spray paper cups with nonstick cooking spray.
In large bowl, combine flour, sugar, baking powder, pumpkin pie spice and salt; mix well.
In small bowl, combine pumpkin, milk, oil and egg whites; blend well. Add to dry ingredients all at once; stir just until dry ingredients are moistened. Spoon batter evenly into sprayed muffin cups. Press 1 cube cream cheese into center of each muffin. Top each with 1/2 teaspoon brown sugar.
Bake at 400°F. for 14 to 18 minutes or until toothpick inserted near center, but not into cream cheese, comes out clean. Immediately remove from pan. Serve warm. Store in refrigerator.