Chill the bowl and whisk for 5 minutes if your kitchen runs warm. It helps the eggs whip better.
Grease and flour the madeleine pan thoroughly. Get into the grooves so nothing sticks.
Preheat the oven to 375°F (190°C). Place the empty pan in the oven for 2–3 minutes before filling for crisper edges.
Melt the butter: Melt 1/2 cup butter and let it cool until warm but not hot. Set aside.
Whip eggs and sugar: In a medium bowl, whisk eggs and sugar for 2–3 minutes until thickened, lightened, and slightly foamy. Aim for a ribbon that falls off the whisk.
Add flavor: Whisk in vanilla and lemon zest until combined.
Combine dry ingredients: In a separate bowl, whisk flour, baking powder, and salt to break up lumps.
Fold gently: Sift the dry mix over the egg mixture in two additions. Fold with a spatula using broad, gentle strokes to keep the batter airy.
Stream in butter: Stir milk into the melted butter. Drizzle the butter-milk mixture down the side of the bowl and fold until no streaks remain. The batter should look silky and slightly thick.
Chill the batter: Cover and refrigerate for 30–60 minutes. This rest improves texture and the signature hump.
Prep the pan: Butter and flour the madeleine molds if you haven’t already. Tap out excess flour.
Fill the molds: Spoon about 1 heaping tablespoon of batter into each mold (about 3/4 full). Do not spread it flat; the oven heat will do the work.
Bake: Bake at 375°F (190°C) for 8–11 minutes. Look for puffed centers, golden edges, and a springy top that bounces back when pressed.
Release and cool: Tap the pan on the counter to loosen. Turn the madeleines out onto a wire rack. Dust with confectioners’ sugar once warm, if you like.
Serve fresh: Enjoy the same day for the best texture—crisp edges and tender middles.
