Key Lime Tart Recipe

Prepare and press crust

Preheat the oven to 350°F (175°C). Place the graham crackers in a food processor and pulse to fine crumbs (or place crumbs in a zip-top bag and crush with a rolling pin). Combine crumbs, 2 tablespoons granulated sugar, finely grated lime zest, and kosher salt in a bowl. Melt the 6 tablespoons unsalted butter and pour over crumbs; toss until evenly moistened and mixture holds together when pinched.

Transfer the crumb mixture to a 9-inch (23 cm) tart pan with a removable bottom (or a 9-inch pie dish). Press the crumbs firmly and evenly over the bottom and up the sides using the bottom of a measuring cup or your fingers (apply even pressure for a compact crust). If you prefer a firmer crust, chill 15 minutes before baking.

Bake the crust for 10–12 minutes, until set and slightly darker at the edges. Remove from oven and set on a wire rack to cool while preparing the filling. Leave oven on.

Warm the heavy cream in a small saucepan or microwave just until steaming but not boiling (~30–45 seconds). This helps temper the yolks and improves texture.

Whisk yolks and sugar

In a medium heatproof bowl, whisk the 5 egg yolks and 1 cup granulated sugar together until smooth and slightly paler, about 1–2 minutes.

Slowly whisk about 2 tablespoons of the warm cream into the yolk-sugar mixture to temper, then whisk in the remaining warm cream until combined.

Add the sweetened condensed milk and whisk until smooth and homogeneous.

Whisk in the 3/4 cup fresh key lime juice and 1 teaspoon finely grated lime zest. The mixture will thicken slightly as the acid reacts with the dairy and yolks.

Pour the filling into the pre-baked crust, smoothing the top with a spatula. Tap the pan gently on the counter to release any air bubbles.

Return the tart to the oven and bake at 350°F (175°C) for 12–18 minutes, until the edges of the filling are set and the center still slightly wobbles when gently shaken (the filling will finish setting as it cools). Avoid overbaking to keep a silky texture.

Remove the tart from the oven and cool on a wire rack for 30–60 minutes. Then refrigerate uncovered for at least 4 hours, preferably overnight, to fully set and develop flavor.

Make whipped cream: chill a mixing bowl and whisk or beaters if possible. Pour 1 cup cold heavy cream into the bowl with 2 tablespoons powdered sugar and 1/2 teaspoon vanilla extract. Whip to soft peaks, being careful not to overwhip.

When the tart is fully chilled, spread or pipe the whipped cream around the edges or over the whole tart as desired. Garnish with thin lime slices or a sprinkle of extra lime zest.

Keep the tart refrigerated and serve within 3 days. Bring to cool-chilled temperature for best texture; remove from pan just before serving if using a removable-bottom tart pan.