Classic French Madeleines

Ingredients

• 3 large eggs, at room temperature
• 1 cup all-purpose flour
• 3/4 cup granulated sugar
• 2 teaspoons vanilla extract
• 1 and 1/4 teaspoons baking powder
• 1 and 1/2 teaspoons lemon zest, finely grated
• 1/2 cup confectioners sugar, sifted, optional
• 1/4 teaspoon salt
• 1 stick unsalted butter, melted until browned