Preheat your oven to 350°F (175°C). Line a cupcake pan with liners.

In a large bowl, beat together the softened unsalted butter and granulated sugar until light and fluffy, about 3-4 minutes.

Incorporate the egg yolks one at a time, mixing well after each addition.

Stir in the milk, fresh lemon juice, and lemon zest until fully combined.

In another bowl, whisk together the flour, baking powder, and salt. Gradually add this to the wet mixture until just combined.

In a separate clean bowl, beat the egg whites and cream of tartar on high speed until soft peaks form.

Gradually add the powdered sugar and continue beating until stiff peaks form.

Gently fold in a small amount of the whipped egg whites into the batter to lighten it, and then carefully fold in the remaining egg whites until no streaks remain.

Divide the batter evenly among the cupcake liners and bake for 20-25 minutes, until a toothpick inserted comes out clean.

Once cooled, pipe the meringue over each cupcake using a pastry bag.

Use a kitchen torch or broil them for a minute to give a beautiful golden color on top.

Let your cupcakes cool for a few minutes before serving.