1. Set the refrigerator to 4°C (40°F)

2. Beat the egg yolks heavy cream sugar key lime juice key lime zest and salt in a medium bowl until fully combined and slightly thickened

3. Crush the graham crackers into fine crumbs using a rolling pin in a sealable bag or in a food processor

4. Stir the melted butter into the crumbs until the mixture resembles wet sand

5. Press the crumb mixture firmly into the bottom and up the sides of a 23cm (9-inch) springform pan using the back of a spoon

6. Pour the filling over the crust and smooth the surface with an offset spatula

7. Chill for at least 3 hours or overnight until completely set

8. Release the springform ring carefully and transfer the pie to a serving plate

9. Slice with a sharp knife dipped in hot water for clean cuts

10. Serve well chilled with whipped cream and a light dusting of lime zest