1 C butter, softened1 C sugar
Preheat oven to 375 and either line a muffin tin with muffin papers or grease the muffin tin. You will need about 18 prepared muffin cups, but you may want to start with only greasing/lining 15 because there's some variation in the capacity of muffin tins.
Alternate stirring the orange juice mixture and flour into the creamed butter mixture, just until everything is incorporated. Don't over mix!
Beat egg whites until stiff peaks form, then gently fold them into the muffin batter by hand, just until no white streaks remain.Divide batter among prepared muffin cups. You want each cup to be about 2/3 full so they don't overflow.
Bake until they turn golden on top and a toothpick inserted into the center comes out clean, about 18-20 minutes.
Yield: About 18 muffins