Key Lime Meringue Recipe

Preheat oven to 350°F (175°C). Lightly grease a 9-inch (23 cm) tart pan with a removable bottom or a 9-inch pie dish.

In a medium bowl combine 1.5 cups graham cracker crumbs, 1/2 cup chopped pecans, 2 tbsp sugar and 1 tsp salt; stir to combine.

Pour in 6 tbsp melted butter and mix with a fork until mixture holds together when pressed. If too dry add up to 1 tbsp more melted butter.

Press the crumb mixture evenly into the bottom and up the sides of the prepared pan, using the bottom of a measuring cup to compact it. Crimp the edge if desired.

Bake crust for 10–12 minutes until fragrant and set. Remove from oven and cool slightly while you make the curd. Reduce oven temperature to 325°F (160°C) if you will warm-fill the tart; otherwise remove from oven and cool completely.

Combine citrus and sugar: In a heatproof bowl whisk together 3/4 cup fresh Key lime juice, 2 tsp lime zest and 1 cup granulated sugar.

Temper the eggs: In a separate bowl lightly whisk 4 egg yolks and 1 whole egg until smooth. Slowly whisk about 2 tablespoons of the lime–sugar mixture into the eggs to temper, then whisk the tempered egg mixture back into the lime–sugar bowl until combined.

Cook curd over simmering water: Set the bowl over (not touching) simmering water (double-boiler). Cook, stirring constantly with a spatula or whisk, until the mixture thickens and reaches about 170–175°F (77–80°C) and coats the back of a spoon, about 8–12 minutes. Do not boil or let the eggs scramble.

Finish with butter and strain: Remove from heat and whisk in 6 tbsp cold cubed butter, one piece at a time, until the curd is smooth and glossy. Add a pinch of salt. For extra silkiness strain the curd through a fine-mesh sieve into a clean bowl to remove any cooked bits or zest if desired.

Assemble filling: If your crust is warm, pour the warm curd into the partially cooled crust. If crust is fully cooled, you may gently warm the curd slightly before pouring so it spreads easily. Smooth the top with an offset spatula.

Chill to set: Cover loosely with plastic wrap (touching the curd to prevent skin) and refrigerate until set, at least 2 hours or up to overnight. The curd should be firm enough to hold meringue on top.

Bring eggs to room temperature (if not already) and ensure mixing bowl and beaters are clean and free of grease; any fat will prevent whites from whipping properly.

In a heatproof bowl set over a pot of gently simmering water (double-boiler), combine 4 egg whites, 1 cup granulated sugar, 1/4 tsp cream of tartar and a pinch of salt. Whisk constantly until the sugar is dissolved and the mixture reaches 140°F (60°C) or feels warm and the sugar no longer grainy when rubbed between fingers, about 3–4 minutes.

Transfer the warmed egg-white mixture to a stand mixer fitted with the whisk (or use a handheld mixer). Whip on medium-high until glossy stiff peaks form and the bowl is cool to the touch, about 6–8 minutes. Add 1/2 tsp vanilla extract in the last 30 seconds and beat to combine.

Top tart with meringue: Remove the chilled curd tart from the refrigerator. Spoon or pipe the meringue onto the curd, making high peaks or swirls to give more surface area for toasting. Ensure the meringue seals to the crust edge to prevent weeping.

Toast the meringue: Use a kitchen blowtorch to brown the meringue evenly until golden-brown peaks form, moving the torch continuously to avoid burning (about 30–60 seconds). If you do not have a torch, place the tart under a preheated broiler set to high about 6–8 inches from the element for 1–2 minutes—watch constantly to prevent burning.

Cool briefly: Let the tart rest at room temperature 10–15 minutes after toasting, then refrigerate for 15–30 minutes before serving to help the meringue set.

Garnish: If desired, sprinkle 1 tsp extra lime zest over the meringue or arrange a few thin lime slices on the side. Lightly dust with powdered sugar if using.

Slice and serve: Use a sharp knife dipped in hot water and wiped dry between cuts for clean slices. Serve chilled or at cool room temperature. Leftovers keep well, covered, in the refrigerator for up to 2 days (meringue may weep slightly).