Preheat the oven to 375 degrees F.
Using an electric mixer beat the egg whites on medium speed with the cream of tartar and the salt until soft peaks form, about 2 minutes. Add the sugar and vanilla and beat until stiff peaks form, about 2 minutes. Add the flour and beat for 2 minutes, scraping down the sides of the bowl as needed. Pour the batter into an ungreased angel food cake pan .
Bake until golden brown and springy when touched, 30 to 35 minutes. (The top of the cake may crack a little.) Remove the pan from the oven and turn it upside down over the neck of a bottle. Let cool completely.
Remove the cake from the pan slice horizontally into three layers. Place the bottom layer on a serving plate. Spoon half of the curd over the cake. Lay the middle layer on top of the curd. Repeat with the remaining curd and top with the last layer of cake. Set aside. Ice the entire cake with the Boiled Icing .
At this point you can eat as is, or lightly brown the boiled icing, carefully with a propane torch*. Slice the cake into individual slices and place on serving plates. Spoon some of the berries over the cake.
In a saucepan , over medium heat, combine the sugar and water. Bring to a boil and cook for 3 minutes. Bring the sugar to 240 degrees F. If crystals appear on the side of a the pan, take a damp pastry brush and brush the sides down.
Meanwhile, combine the whites, salt, and tartar in the bowl of an electric mixer, fitted with wire whip. Beat on low speed until soft peaks form. Increase the speed to medium-high and beat until stiff peaks form.
In a steady stream, add the sugar syrup to the whites and continue whipping until the icing is spreadable. Whip in the vanilla.
Yield: about 2 cups Zest all of the lemons and set aside. Juice the zested lemons and strain the juice, you should get about 3/4 cups of juice.
In a small mixing bowl, whisk the yolks and sugar until smooth. Stir in the lemon juice . Pour the mixture into a non-reactive saucepan. Over medium heat, bring to a simmer . Reduce the heat to low and continue to cook, stirring constantly with a wooden spoon, until the mixture thickens and coats the back of a spoon. Remove from the heat and pour into a glass bowl. Stir in the butter, one tablespoon at a time. Cool to room temperature.
Yields: about 2 1/2 cups Combine in a mixing bowl and mix well. Cover and refrigerate for at least 1 hour.
Just before serving, stir in the mint.
Yields: about 2 cups *Propane Gas Torch Warning Propane gas torches are highly flammable and should be kept away from heat or flame, and should not be exposed to prolonged sunlight. Propane gas torches should only be used in well-ventilated areas. When lighting a propane gas torch, place the torch on a flat, steady surface, facing away from you. Light the match or lighter and then open the gas valve. Light the gas jet, and blow out the match. Always turn off the burner valve to "finger tight" when finished using the torch. Children should never use a propane gas torch without adult supervision.