Lemon Poppyseed French Madeleines

Madeleine Batter
1 Whisk together flour, salt, and baking powder in a small bowl. Set aside.
2 In the bowl of a stand mixer with whisk attachment, combine sugar, eggs, egg white, zest, and lemon juice. 
3 Whisk on medium high speed for 8-10 minutes until a light airy foam like consistency is formed. Almost like a soft meringue.
4 Remove bowl from mixer and slowly begin folding in flour mixture a quarter at a time, with the poppy seeds.
5 Then, slowly pour in the cooled melted butter and gently fold into the mixture.
6 Cover bowl with plastic wrap and set in the fridge for 45 minutes. 
7 Preheat oven to 350 F (176 C).
8 Brush melted butter across each shell shape to prevent sticking.
9 Fill each madeleine well with a heaping Tbsp of batter. Don't flatten the batter, it will melt and fill the shell shape as it bakes. 
10 Bake for 10-12 minutes until a light golden brown crust has formed around the edges.
11 Let cool in pan for 5 minutes then remove and eat!