Whisk together flour and baking powder in a medium bowl and set aside.

Use an electric mixer with a whisk attachment, on medium-high speed beat together the eggs and sugar until the mixture is thicken and pale in color, about 5 minutes. Beat in lemon zest.

Use a rubber spatula to gently fold the flour mixture into the egg mixture just until blended. Fold in the cooled butter and mix just until blended.

Cover the batter and refrigerate for about 1 hour or until completely chilled.

Preheat the oven to 375°. Put a rack in the top third of the oven. Spray the madeleine cups with non-stick baking spray with flour.

Use a #40 cookie scoop to spoon batter 1 tablespoon batter into the molds.

Bake for about 10 - 12 minutes until the edges are golden brown and middle is set. Transfer the pan to a cooling rack for 5 minutes before unmolding the cakes onto a cooling rack.

While the cakes are cooling, make the lemon glaze in a mixing bowl by whisking together the powdered sugar and lemon juice until smooth.

Dip the scalloped side of the cake in the glaze, letting excess drip back in to the bowl. After dipping, put each one back on the cooking rack, scalloped side up to cool. Move the madeleines around on the rack a little bit occasionally until they’re cool so they don’t stick to the rack.