Preheat oven at 375 F (190 C). Brush melted butter (not in the ingredients list) in the shell indentations of the Madeleine pan.

Beat eggs and sugar in a bowl of a stand mixer to blend for 2 minutes. Add flour, grated Yuzu peel, and salt, and mix for a couple of minutes. Add melted butter gradually to the batter until well mixed, scraping down the sides.

Put the batter in a piping bag. Fill the shell indentations of the Madeleine pan about 3/4 full.

Bake for 13-15 minutes, or until slightly browned. Remove Madeleines from the pan and cool.

Dust with powdered sugar.