1Preheat oven to 350F.
2In a bowl, mix the flour, baking powder, and salt.
3In another bowl, add the butter and sugar and beat until pale. Add the eggs one at a time, then the vanilla extract and lemon zest.
4Gradually, add the flour mixture and mix to a smooth batter.
5Add the buttermilk and lemon juice and mix.
6Pour the batter into muffin pans.
7Bake for 20 to 25 minutes depending on the size of the pans. Remove from the pans and cool on a wire rack.
8Lemon Curd Preparation:
9Wash the lemons, then zest and juice them.
10In a saucepan, add the lemon juice and zest.
11Add the cornstarch and the sugar.
12Gently whisk the mixture on low heat.
13In a bowl, beat the eggs.
14Remove the lemon mixture from heat and gradually add the beaten eggs.
15Keep mixing this preparation without stopping, preferably with a whisk so that the bottom does not stick.
16Put the pan back on the stove on low heat and keep stirring until thickened, about 5 minutes.
17Remove from heat and pour directly into a bowl to cool.
18With a teaspoon, drop a little lemon curd on top of the cold cupcakes.
19Egg White Frosting Preparation:
20In a saucepan, add 165 grams of sugar and water.
21Bring the syrup to a boil, stirring occasionally. Bring the temperature up to 450F.
22Meanwhile beat egg whites until stiff.
23When peaks form, add 1 tablespoon of glucose. Keep whipping and lower the mixer speed to pour the boiling syrup in the whites eggs. Simply lower the speed but do not stop the mixer.
24Gradually, increase the speed until the mixture is completely cool, about 10 minutes.
25When the mixture is cold, place it in a piping bag with a fluted tip.
26Carefully, squeeze out a small amount of frosting on each cupcake on top of the lemon curd.
27Sprinkle with confectioner's sugar and toast quickly with a torch.