Ingredients
Scale
- 1 ½ cups graham cracker crumbs (about 10–12 full sheets)
- 1/3 cup granulated sugar
- 6 tablespoons unsalted butter, melted
- 28 ounces sweetened condensed milk (two 14-ounce cans)
- ½ cup sour cream (full fat)
- ¾ cup key lime juice (freshly squeezed or high-quality bottled)
- 1 tablespoon key lime zest
- 1 ½ cups heavy whipping cream, chilled
- 3 tablespoons powdered sugar
- 1 teaspoon vanilla extract
Instructions
- Preheat your oven to 350°F (175°C). In a medium bowl, combine the graham cracker crumbs, granulated sugar, and melted butter. Stir until the mixture looks like wet sand. Press the mixture firmly into the bottom and up the sides of a 9-inch pie plate. Use the bottom of a measuring cup to ensure an even, tight layer. Bake the crust for 8 to 10 minutes until it is lightly golden and fragrant. Set it aside to cool slightly while you prepare the filling.
- In a large mixing bowl, whisk together the sweetened condensed milk, sour cream, key lime juice, and lime zest. Whisk vigorously until the mixture is completely smooth and thick. The acid in the lime juice will begin to set the proteins in the milk immediately. Ensure there are no streaks of sour cream remaining.
- Pour the lime mixture into the pre-baked graham cracker crust and spread it evenly with a spatula. Return the pie to the oven and bake for 15 to 18 minutes. You are looking for the edges to set slightly, but the center should still have a very slight jiggle when moved. Do not let the top brown. Remove the pie from the oven and let it cool to room temperature on a wire rack.
- Once the pie reaches room temperature, cover it loosely and refrigerate for at least 3 hours, though overnight is best. This chilling period is crucial for the pie to fully set and for the flavors to meld together. Never skip this step, or the pie will be too soft to slice cleanly.
- In a cold bowl, beat the heavy whipping cream, powdered sugar, and vanilla extract until stiff peaks form. Pipe or spread the whipped cream over the chilled pie. Garnish with extra lime zest or thin lime slices. Slice and serve immediately while cold.
- Cook Time: 45 minutes