Preheat oven to 350 degrees. Butter and flour madeline pan or spray with nonstick cooking spray.

In a microwave safe bowl, melt butter.

In a large bowl, beat eggs, sugar, salt, and vanilla extract for 5 minutes on medium high speed.

Once batter is pale and have doubled in volume, gently fold in lemon and lime zest.

In a separate bowl, sift together flour, salt, and baking powder.

Add sifted flour in three parts, gently folding flour into egg batter after each addition.

Slowly pour butter into batter while folding it in.

Spoon about 1 and ½ tablespoons of batter into each shell.

Bake Madeleines for 8 to 10 minutes.

Allow to cool for 5 minutes before removing from pan then cool completely.

In a small bowl, combine powdered sugar and lemon and lime juice; stir until smooth.

Either dip tops of madeleines into the glaze or pour over. Place on wire rack to dry.

Enjoy immediately or store in an air tight container for up to one week. Freeze for up to one month.