For lemon curd, whisk together lemon juice, eggs and yolk, and sugar. Whisk in butter and add lemon zest. Place bowl over a pot of simmering water and whisk steadily, but gently, until curd becomes thick and pale and creamy, about 10 to 15 minutes. Remove from heat and chill until ready to use.
For lemon sponge, preheat oven to 350°F (180°C). Grease and sugar 6 (5-ounce) ramekins, and place a disc of parchment paper at the bottom of each ramekin. Place eggs in their shells in a bowl, cover with hot tap water and let sit for a few minutes. Break eggs into a bowl and whip eggs and sugar in a mixer fitted with the whisk attachment until very pale and airy, about 10 to 15 minutes. Sift together dry ingredients into a separate bowl. Combine butter, vanilla, zest and juice and set aside. Reduce speed on mixer to medium and add dry ingredients quickly to egg mixture, but not all at once, until almost blended. Add butter mixture, and mix just until blended.
Spoon cake mixture evenly among ramekins, leaving 1/2 inch at the top for expansion. Spoon a generous dollop of lemon curd into the centre of each cake. There is no need to press it in as it will sink during baking. Bake for 20 to 25 minutes, until cake is golden brown and springs back when you touch it.
To serve, turn warm cakes out onto dessert plates. Dust tops with confectioners' sugar and serve with a piped bit of the remaining chilled lemon curd beside it.
Makes 6 servings.
Date: July 17, 2004