Instructions:

Preheat the oven to 425 degrees.

Bake the pie shell for 12 minutes at 425 and remove from the oven.

Reduce heat to 350 degrees.

Process the sugar and the zest in a food processor until zest is finely ground.

Whisk together the water, sugar mixture, cornstarch and salt in a medium saucepan.

Bring the mixture to a boil over medium heat, whisking constantly and boil for 1 minute, until mixture is smooth and almost transparent.

Remove the pan from the heat.

Whisk together the egg yolks and lemon juice in a medium bowl.

Add ½ cup of the hot cornstarch mixture to the yolk mixture and whisk to blend.

Continue adding the cornstarch mixture ½ cup at a time until it's all mixed in.

Return the mixture to the saucepan, bring to a boil for 1 minute or until thick.

Remove the pan form the heat, pour the filling through a strainer into a bowl.

Whisk in the butter.

Fill the cooled pie shell with the hot filling.

To make the meringue:

whisk together the sugar and cornstarch in a small saucepan, add the water and bring to a boil.

Whisking constantly over high heat, boil for 1 minute.

Beat the egg whites with an electric mixer on medium speed in a clean bowl, just until foamy.

Increase the speed to medium high, add the salt and beat to form soft peaks.

Pour in the cornstarch mixture in a fine stream while the beaters are running.

Beat until stiff peaks are formed.

Top the pie filling with the meringue mixture.

Make certain that the meringue seals in the filling.

Bake for 15 to 17 minutes or until the meringue is cooked through and golden brown.

Cool and serve.