1 cup superfine sugar (place sugar in a food processor and process until very fine)
½ cup egg whites
Filling:
½ cup heavy cream
1 T sugar
1 tsp lemon zest finely grated
Procedure
Preheat oven to 250 degrees
Line baking sheets with parchment paper.
At full speed, beat the egg whites until stiff and dry.
Still at full speed, gradually add the sugar, giving it a minute to beat in between additions. Once all of the sugar is incorporated the mixture should be dense and shiny.
Scoop half the meringue at a time into a large pastry bag fitted with a half inch nozzle.
With one hand holding the nozzle and the other hand squeezing the meringue, pipe out thick lady finger shaped strips. Keep the pastry bag perpendicular to the cookie sheet and about ½ inch above the paper. Work quickly.
Bake for 1 hour on a rack in the middle of the oven.
Turn off the oven after an hour and leave the meringues in the oven until cool.
Beat the cream until thick and then beat in the sugar and the lemon zest.
Pipe the cream between 2 meringue cookies making a sandwich.