Ensure the bowl and beaters are completely clean and grease-free when whipping egg whites to ensure proper volume.
The meringue shell can be made a day in advance and stored in an airtight container at room temperature. Assemble the pie just before serving to maintain the crisp texture of the shell.
For a variation, you can fill the crust with fresh berries instead of the custard mixture and serve with a side of whipped cream.
Use a double boiler carefully to avoid curdling the egg yolks. The mixture should be thick enough to coat the back of a spoon.