Beat sugar and butter together with electric mixer for 2 minutes..
Add egg whites one at a time, beating on low speed for about 30 seconds after each.
Add sour cream, milk, vanilla and extracts and beat on low speed for about 1 minute.
In separate bowl combine dry ingredients.
Add to wet ingredients gradually, and beat lightly after each addition.
Fill lined muffin tins ⅔ full.
Bake at 400 degrees for 5 minutes and then reduce heat to 350 degrees and bake additional 8-10 minutes, or just until cake springs back when lightly touched in center.
After 5 minutes remove cupcakes from pan and allow to cool completely on wire rack before frosting.
Orange Cream Cheese Frosting
Blend butter and cream cheese until fluffy.
Stir in extract, zest and and sugar and stir until smooth.
Notes
Frosting is best if made about 12 hours ahead of time and refrigerated. Allow to come to room temperature before using.If muffin tins are filled ¾ full 12 cupcakes can be made.