Preheat the oven to 200°F/100°C. Prepare a sheet of parchment paper by tracing a 9″ / 23 cm round circle on it and flipping it over onto a baking sheet. You should still be able to see the circle outline through the paper.
In a large bowl, beat the egg whites with the salt on medium-high speed until soft peaks form.
Combine the sugar and cornstarch and gradually add it to the egg whites with the mixer running, 1 tablespoon at a time, until the meringue looks glossy. Whisk in 1 tsp white wine vinegar and 2 teaspoons vanilla extract.
Spread the meringue inside the circle, creating a crater by making the sides a little higher than the middle.
Bake for 1- ½ hour. Turn off the oven and leave the door closed. Leave the meringue in the oven for at least 1 hour. Take it out of the oven and let it cool completely.
To make the Lemon Custard
Heat the milk over medium high heat and bring it to a simmer, almost to a boil.
While the milk is being heated, place the sugar, egg, lemon zest, cornstarch and salt in a bowl. Whisk until you have a thick, smooth mix.
As soon as the milk starts to bubble, remove it from the heat. Slowly whisk half of the hot milk with the egg to temper the mix. This keeps the egg from turning to scrambled eggs when you add them to the simmering milk.
Pour the egg/milk mixture back into the remaining simmering milk. Bring to a boil, stirring constantly with a whisk, until the mixture thickens.
Remove from the heat and add the butter and the vanilla extract. Whisk the butter, until it’s completely mixed in, then add lemon juice and whisk again.
Pour the custard into a bowl and immediately cover the surface with plastic wrap, making sure the plastic wrap is touching and sealing the whole surface. This is to prevent a custard skin from forming on top.
Let the custard cool down to room temperature and then let it chill in the fridge for a few hours, until it’s completely chilled. With a hand mixer at medium speed, whip custard to become fluffy for about 1 minute, just before using it.
Up to an hour before serving, whip together heavy cream, powdered sugar and vanilla extract until firm peaks form.
Top meringue with the lemon custard, whipped cream and strawberries or fresh fruits. Refrigerate for about ½ – 1 hour and serve.
