Beat room temperature egg whites and pinch of salt with a whisk in a stand mixer or with hand beaters until soft peaks form.
Slowly add the cold water, the egg peaks will initially slump. Continue to beat until soft peaks form once again.
Mix the sugar and corn starch in a bowl then slowly add this while beating into the egg whites. When the sugar and corn starch has been thoroughly incorporated beat for one more minute.
Start beating the egg whites at high speed while adding the vinegar. Continue beating until very stiff peaks form.
Place either a silicon baking sheet (my favorite) or some parchment paper on a baking sheet. Alternatively parchment paper can be used to line a spring form pan.
Place the meringue onto the baking sheet or spring form pan shaping the mass into a round with raised edges.
Bake in the oven for approximately 45 minutes until surface has some gentle golden coloring. Turn off the oven and open the oven door a crack and allow the base to cool in the oven for 1 hour more.
Lemon Curd
In a heat resistant bowl beat the egg yolks until they are of even consistency.
In a saucepan mix the sugar, cornstarch, lemon juice and butter and heat at medium high whisking while heating. to a simmer. When a simmer is reached continue to simmer while whisking for another minute.
While whisking the egg yolks slowly pour the simmered sugar, cornstarch, lemon juice and butter into the eggs.
Once the eggs have been mixed into the hot lemon syrup add the whole mix back into the saucepan and resume simmering while constantly steering over medium heat until thickened (about 2 minutes). Remove from heat and transfer into a heat resistant bowl and cover the bowl with plastic wrap and allow to cool.
When both the meringue base and the lemon curd have cooled pour the curd into the center of the meringue base and distribute. Top with fresh fruit if desired.