Using an electric mixer beat eggs whites, key lime juice, cream of tartar, salt and lime zest on high speed until stiff peaks form.
Reduce speed to low and gradually stir in sugar until just combined.
Gradually sprinkle in cake flour and gently fold into mixture. Don’t over mix. Pour batter in a 9 or 10 inch angel food tube pan and bake for 35-40 minutes until golden brown and springs back when touched. Let cool completely before carefully removing from pan.
Key Lime Glaze
In a small bowl stir together confectioners sugar, key lime juice and lime zest. Poke small holes on top of cake and drizzle glaze over cake.
Fresh Lime Whipped Cream
Add heavy whipping cream, sugar and lime zest to a large bowl. Using an electric mixer, beat on high for 3-4 minutes until it becomes thick and creamy.