Preheat your oven to 350°F (175°C) if you're making a homemade graham cracker crust. If you're using a store-bought crust, you can skip this step.
In a mixing bowl, whisk together the egg yolks and grated lime zest until well combined.
In a saucepan, combine the freshly squeezed lime juice and granulated sugar over medium heat. Stir continuously until the sugar has dissolved and the mixture is heated through but not boiling.
Gradually pour the lime juice and sugar mixture into the egg yolks, whisking constantly to prevent the eggs from cooking.
Once combined, return the mixture to the saucepan and cook over low heat, stirring constantly, until it thickens slightly. This should take about 5-7 minutes. Do not let the mixture boil.
Once thickened, remove the lime custard mixture from the heat and stir in the heavy cream until fully incorporated.
Pour the lime custard mixture into the prepared graham cracker pie crust, spreading it out evenly with a spatula.
Bake the pie in the preheated oven for 10 minutes, or until the filling is set but still slightly jiggly in the center.
Remove the pie from the oven and let it cool to room temperature.
Once cooled, refrigerate the pie for at least 3-4 hours, or until chilled and set.
Before serving, garnish the Key Lime Pie with whipped cream and lime slices if desired.
Slice and serve your delicious Key Lime Pie without condensed milk, and enjoy the tangy, creamy goodness!
