Preheat the oven to 400°F. Lightly butter a madeleine pan; set aside. Into a medium bowl, sift together flour, baking powder, and salt. Set aside.
In a mixing bowl, beat the eggs, yolks, granulated sugar, vanilla, and lemon juice and zest until thick and pale, about 5 minutes. Beat in the melted butter. Using a rubber spatula, gently fold the flour mixture into the egg mixture; let rest 30 minutes at room temperature.
Pour the batter into the prepared pan, filling the molds three-quarters full. Bake until the cookies are crisp and golden around the edges, 7 to 8 minutes. Transfer the pan to a wire rack to cool slightly before inverting the cookies onto a serving platter. Dust with confectioners’ sugar, if desired.
