4 cups
(500 grams) sifted all-purpose flour
1/2 teaspoon
baking powder
1 cup
plus 6 tablespoons (300 grams) softened salted butter
1 1/3 cups
(250 grams) granulated sugar
2
medium eggs, lightly beaten (or one big old American-sized egg)
1 teaspoon
vanilla sugar (or vanilla extract if you have no vanilla sugar)
1
egg white, for brushing the cookies with