01 -
Preheat the oven to 350 degrees Fahrenheit (175 degrees Celsius).
02 -
Combine sweetened condensed milk, key lime juice, sour cream, and grated lime zest in a bowl; mix well. Pour the mixture into the prepared graham cracker crust and place the pie on a baking sheet.
03 -
Bake in the preheated oven for 5 to 8 minutes, until tiny pinhole bubbles burst on the surface of the pie. The filling will remain wobbly but should not brown.
04 -
Transfer the pie to a wire rack to cool completely, then refrigerate until thoroughly chilled, about 1 hour. Garnish with lime slices and whipped cream, if desired, before serving.