Preheat your oven to 350°F (175°C) and prepare three 9-inch round cake pans by greasing and flouring them.

Whisk together the flour, baking powder, and salt in a medium bowl until well combined.

Cream the softened butter and granulated sugar in a large mixing bowl until light and fluffy.

Add the eggs, lemon zest, and lemon juice to the butter mixture, beating until well blended.

Combine the dry ingredients with the wet ingredients, alternating with the milk.

Divide the batter evenly into the prepared cake pans. Bake for 30–35 minutes or until a toothpick inserted in the center comes out clean.

Allow the cakes to cool in the pans for 10 minutes before transferring them to wire racks to cool completely.

Prepare the lemon curd by whisking together the sugar, cornstarch, and salt in a medium saucepan.

Gradually add the water while whisking to ensure no lumps.

Heat the mixture over medium heat until it begins to boil, stirring constantly.

Temper the beaten egg yolks and whisk the yolk mixture back into the saucepan.

Cook for an additional 2–3 minutes until thickened.

Remove from heat and stir in the lemon juice, butter, and lemon zest. Let the curd cool completely.

Beat the egg whites and cream of tartar in a clean mixing bowl on medium speed until soft peaks form.

Continue to gradually add the granulated sugar, beating until stiff peaks form.

Layer the first cake on a serving plate and spread a generous layer of lemon curd over the top.

Repeat this with the second layer and more lemon curd before adding the final layer.

Spread the meringue over the top and sides of the cake, using a spatula to create peaks.

Brown the meringue gently with a kitchen torch or under the broiler for a few minutes.

Cool the cake slightly before slicing it into pieces.