In a medium bowl, cream together 1/4 cup of the sugar with the softened butter and lemon zest until pale and fluffy, 2 to 3 minutes. Add the egg yolks and mix in until fully combined. Set aside.
Place the egg whites in a large, clean bowl. Whisk them while gradually pouring in the remaining 1/2 cup of sugar, then continue to whisk until stiff peaks form, about 5 minutes. Fold roughly 1/3 of the egg mixture into the butter mixture to loosen it.
Add the remaining whisked egg white mixture into the butter mixture. Sift in the flour, baking powder, and salt. Gently fold the mixture together just until no flour-y patches remain—be careful not to over-mix it.
Chill the batter for at least 2 hours, or up to 24.
When you’re ready to bake, preheat your oven to 375º F, then generously butter and flour a madeleine pan. Fill each cavity of the pan about 3/4-full with batter, then bake for 12 to 15 minutes until the madeleines are slightly domed and have golden-brown edges.
Pop the madeleines out of their pan onto a cooling rack. Allow to cool for a few minutes, then dust with powdered sugar, if desired, and serve alongside your toast and a hot cup of tea.
Passionate about cakes, roasted vegetables and anything involving Maldon salt or maple syrup. Izy is a student living in London, UK who spends her spare time blogging and rambling on topwithcinnamon.com