Key Lime Tart Recipe

Prepare pan

Preheat oven to 350°F (175°C). Lightly butter a 9-inch (23 cm) tart pan with removable bottom or a 9-inch tart ring on a baking sheet.

In a medium bowl combine graham cracker crumbs, granulated sugar, and salt. Pour in melted butter and stir until evenly moistened and mixture holds together when pressed.

Press crumb mixture firmly and evenly into the bottom and up the sides of the tart pan (about 1/4–1/2 inch thick). Use the bottom of a measuring cup for an even compact crust.

Bake crust for 8–10 minutes until set and fragrant. Let cool on a rack while you prepare the filling. Reduce oven to 300°F (if using the oven later) or simply proceed—bavarian is chilled, so no further baking needed.

Bloom gelatin: sprinkle the gelatin over 2 tbsp cold water in a small bowl and let sit for 5 minutes until swollen.

In a medium saucepan combine whole milk, heavy cream, and the scraped vanilla bean seeds plus the pod. Warm over medium heat until it just begins to steam and small bubbles form at the edge (do not boil). Remove from heat, cover, and let steep for 10 minutes to infuse vanilla.

While the dairy steeps, whisk together egg yolks and granulated sugar in a heatproof bowl until smooth and slightly pale (ribbon stage).

Remove vanilla pod from milk mixture, then slowly temper the warm milk into the egg yolks: drizzle about 1/3 of the warm milk into the yolks while whisking constantly to raise their temperature. Then pour the tempered yolk mixture back into the saucepan with the remaining milk.

Cook the custard over medium-low heat, stirring constantly with a wooden spoon or spatula, until it thickens enough to coat the back of the spoon (nappe) — about 170–175°F (77–80°C). Do not boil (avoid curdling).

Remove from heat. Stir the bloomed gelatin into the hot custard until completely dissolved. Add key lime juice and lime zest, and taste. If needed, stir in up to 1 tsp powdered sugar for slight sweetness balance. Mix thoroughly.

Transfer the custard to a clean bowl and let it cool, stirring occasionally, until it is just warm (about 25–30°C / 77–86°F). To expedite, set the bowl over an ice bath and stir gently until temperature is reached.

When the custard is warm (not set), fold in half of the whipped cream (or lightly whipped cream to soft peak) to lighten, then gently fold in the remaining cream until fully incorporated and smooth. This creates a bavarian mousse texture.

Pour or pipe the bavarian filling into the cooled graham crust, smoothing the top. Tap gently to remove air pockets. Chill in refrigerator at least 4 hours, preferably overnight, until fully set.

Prepare mango puree if not already: peel and dice ripe mangoes and blend until smooth. Strain if desired for ultra-smooth sauce.

In a small saucepan combine 1 cup mango puree, 2 tbsp sugar, 1 tsp lime juice and a pinch of salt. Whisk to combine and warm over medium-low heat.

Stir the cornstarch slurry (1 tsp cornstarch + 1 tsp cold water mixed) into the warm mango and cook, stirring constantly, until sauce thickens slightly, about 1–2 minutes. If too thick, whisk in up to 1 tbsp cold water to reach a pourable sauce consistency. Remove from heat and cool to room temperature, then chill until serving.

When the bavarian tart is fully set, remove it from the tart pan and place on serving platter.

Spoon or drizzle mango sauce across the center of the tart in a decorative pattern, or serve the sauce on the side. Reserve some sauce to serve alongside slices.

Top tart with dollops of lightly sweetened whipped cream around the edge or a central rosette. Sprinkle lime zest over the whipped cream and mango sauce for brightness.

Garnish with thin lime slices or candied lime and mint leaves, if using. Keep chilled until serving. For best texture, serve within 24–48 hours.