Place your crust in a pie dish. Brush lightly with melted butter. Bake until golden and crisp. Let it cool fully before adding the lemon filling.

In a saucepan, add sugar, cornstarch, and salt. Whisk them well together first. This helps stop lumps and gives the lemon filling a smooth texture.

Slowly pour in water while whisking. Place the pan over medium heat. Stir often until the mixture thickens and starts bubbling gently.

Beat egg yolks in a bowl. Add a little hot mixture slowly. Then pour yolks back into the saucepan. Cook gently while stirring well.

Mix in fresh lemon juice, lemon zest, and butter. Stir until smooth and glossy. The kitchen will smell bright, fresh, and sweet with lemon.

Pour warm lemon filling into the baked crust. Spread evenly with a spatula. Keep it warm while you prepare the soft meringue topping.

Beat egg whites until foamy. Add cream of tartar. Slowly add sugar and vanilla. Beat until thick, shiny peaks form and hold shape.

Spread meringue over warm filling. Cover every edge carefully. Make soft swirls with a spoon. This gives the pie a lovely bakery look.

Bake for about 10 minutes. The top should turn light golden brown. Cool fully, then chill before slicing for the best clean slices.