Key Lime Tart Recipe

Preheat and prepare pan

Preheat the oven to 350°F (175°C). Lightly butter a 9-inch tart pan with a removable bottom or spray with nonstick spray.

Combine the graham cracker crumbs, granulated sugar, melted butter, and salt in a medium bowl. Mix until the crumbs are evenly moistened and hold together when pinched.

Press the crumb mixture into the bottom and up the sides of the prepared 9-inch tart pan, using the bottom of a measuring cup or a flat glass to compress it firmly and evenly. Make the edges about 1/4-inch higher than the pan rim to account for shrinkage.

Bake the crust for 8–10 minutes until fragrant and set. Remove from the oven and let cool slightly while you prepare the filling. Leave the oven on.

Zest the limes first. Measure 1 tablespoon of lime zest and reserve 1/2 teaspoon for garnish if using. Juice enough key limes (or regular limes) until you have 3/4 cup of juice. Strain if desired to remove seeds and excess pulp.

In a medium bowl or the bowl of a stand mixer, whisk together the sweetened condensed milk, lime juice, lime zest, eggs and egg yolks, heavy cream, vanilla extract, and a pinch of salt until the mixture is smooth and homogeneous. Whisk just until combined — do not overbeat to avoid introducing too much air.

Pour the filling into the prebaked graham cracker crust and smooth the top with a spatula. Tap the pan gently on the counter to release any trapped air bubbles.

Bake the tart at 325°F (163°C) for 18–22 minutes, or until the edges are set and the center still slightly jiggles when the pan is gently shaken. The filling will continue to set as it cools. Do not overbake to avoid curdling or cracking.

Remove the tart from the oven and let it cool on a wire rack for 30–45 minutes at room temperature. Then refrigerate the tart (uncovered) for at least 3 hours, preferably 4–6 hours or overnight, to fully set and develop flavor.

About 10–15 minutes before serving, make the whipped cream. In a chilled mixing bowl, whip 1/2 cup cold heavy cream with 1 tablespoon confectioners' sugar until soft peaks form. Do not overwhip.

Spread or pipe the whipped cream decoratively around the edge of the chilled tart or in small dollops. Sprinkle reserved lime zest over the top and garnish with thin toasted lime wheels or slices if desired. To toast lime slices: place thin lime rounds on a parchment-lined baking sheet and broil or bake at 400°F for 6–8 minutes until slightly dehydrated and brown at the edges (watch carefully).

Keep the tart refrigerated until ready to serve. Slice with a warm knife (run under hot water and dry between cuts) for clean slices.