Heat oven to 400°F. Line 12 regular-sized muffin cups with paper baking cups; lightly coat with cooking spray.
Combine the flour, baking powder, ginger, cinnamon, baking soda and salt in a medium bowl. Using a pastry blender or two forks, cut in butter until mixture resembles coarse crumbs. Make a well in the center of the flour mixture.
Mix the egg, milk, sour cream, brown sugar, and molasses in another bowl. Add egg mixture and apples to the flour mixture; stir just until moistened. Spoon batter into the prepared muffin cups. Combine the granulated sugar and crystallized ginger in a small bowl; sprinkle over muffin batter.
Bake muffins for 18 to 20 minutes or until a wooden pick inserted into the center of a muffin comes out clean. Cool in pan on a wire rack for 10 minutes; serve warm.