Frozen Key Lime Pie Recipe

Line a 9-inch (23 cm) springform pan or pie dish with parchment on the bottom for easier removal. Preheat oven to 350°F (175°C) if you prefer to briefly bake the crust. (Baking is optional but helps set the crust.)

Combine graham cracker crumbs, granulated sugar and salt in a medium bowl. Stir in melted butter until mixture resembles wet sand and holds together when pressed.

Press the crumb mixture evenly into the bottom and slightly up the sides of the prepared pan, using the bottom of a measuring cup to compact the crust firmly and evenly.

If baking: bake crust 8–10 minutes until fragrant and slightly darker, then remove and cool completely. If not baking: chill crust in the freezer 20 minutes to firm before filling.

In a medium bowl, whisk together mascarpone, sour cream and the sweetened condensed milk until smooth and lump-free. Use a rubber spatula to scrape sides.

Add key lime juice, lime zest, vanilla extract and salt. Whisk until fully incorporated and mixture is glossy. Taste and adjust lime or salt if desired — filling should be bright, tangy and slightly sweet.

Pour the filling into the prepared crust, smoothing the top with an offset spatula. Tap the pan gently on the counter to remove any air bubbles and level the surface.

Cover tightly with plastic wrap and freeze until firm, at least 6 hours or preferably overnight.

Place a medium metal bowl and beaters in the freezer for 10 minutes to chill (optional but helps volume). Meanwhile, melt the white chocolate: place finely chopped white chocolate in a heatproof bowl and microwave in 15–20 second bursts, stirring between bursts, until smooth. Alternatively, melt over a double boiler. Let chocolate cool to lukewarm but still pourable (about 10–15 minutes).

Pour cold heavy cream into the chilled bowl and begin whipping on medium speed. When cream starts to thicken and soft peaks form, add powdered sugar, vanilla and salt.

With the mixer running on low, drizzle in the cooled white chocolate and continue whipping to medium-stiff peaks. Stop as soon as peaks hold their shape but are still glossy — do not overwhip or the cream will break.

Taste and adjust sweetness if needed. Keep the white chocolate whipped cream chilled until ready to serve.

Remove the frozen pie from the freezer and let sit at room temperature for 6–10 minutes to ease slicing (longer if extremely firm). If using a springform, release the ring and transfer pie carefully to a serving plate if desired.

Top the pie with dollops or a piped border of white chocolate whipped cream. If you prefer a fully frosted top, spread whipped cream evenly over the surface immediately after removing the pie from the freezer.

Garnish with extra lime zest, a few thin lime slices or wedges and a sprinkle of crushed graham crackers. For cleaner slices, dip a sharp knife in hot water, dry it, and wipe between each cut.

Slice and serve immediately. Store any leftovers tightly covered in the freezer for up to 2 weeks; allow frozen slices to sit 10–15 minutes at room temperature before serving for best texture.