Madeleines or genoise cake

This recipe can be doubled. I usually brush the pan with melted butter and then flour the pan.
1/2 cup butter, unsalted, melted
3 eggs
2/3 cup sugar
1 cup flour
1/2 teaspoon baking powder
 1/4 teaspoon salt
 1-2 teaspoon vanilla
Zest of 1 lemon Juice of 1 lemon

Melt butter and set aside. Beat eggs and sugar until it forms ribbons. Batter thickens and turns a light, pale yellow color. Zest the lemon. Add cooled melted butter. Refrigerate 20-30 minutes. Meanwhile prepare pan. Melt butter an additional 1-2 T. Butter. Brush pan with butter and sprinkle with flour. Juice the lemon. After 20-30 minutes, add remaining ingredients. Use small scooper or drop by teaspoon.Bake at 350 for 8-10 minutes. 

Doubled

2 sticks of butter, melted
6 eggs
1 and 1/3 cups sugar
2 cups flour
1 t. Baking powder
1/2 t. Salt
2-4 teaspoons vanilla
Zest and juice of 2 lemons