Preheat oven to 180°C (350°F) and pre-bake pie crust 10–12 minutes until lightly golden, then cool.
In a saucepan, combine raspberries, sugar, cornstarch, salt, and water; cook over medium heat until thick and glossy.
Whisk egg yolks in a bowl; slowly add a small amount of hot raspberry mixture while stirring to temper.
Pour tempered yolks back into saucepan and cook 2–3 minutes until thick and smooth.
Remove from heat; stir in butter, lemon juice, and lemon zest.
Pour filling into cooled crust and spread evenly.
Let pie cool at room temperature, then refrigerate 3–4 hours to set.
Top with whipped cream and extra raspberries before serving.