Step 1

Adjust oven rack to middle position and heat oven to 375 degrees. Grease 12-cookie madeleine mold. Whisk flour and salt together in small bowl.

Step 2

Using stand mixer fitted with paddle, beat eggs and yolk on medium-high speed until frothy, 3 to 5 minutes. Add sugar and vanilla and beat until very thick, 3 to 5 minutes. Using rubber spatula, gently fold in flour mixture, followed by melted butter.

Step 3

Spoon half of batter into prepared mold, filling mold to rim. Bake until madeleines are golden and spring back when pressed lightly, about 10 minutes, rotating mold halfway through baking.

Step 4

Let cookies cool in mold for 10 minutes. Remove madeleines from mold and transfer to wire rack. Repeat with remaining batter. Let madeleines cool completely before serving.