Prepare the crust. Blitz the gingersnaps into fine crumbs in a food processor or by placing them in a zipper bag and crushing them with a rolling pin. Combine crumbs with the butter and salt until all the crumbs are evenly moistened. Press the crumbs into a 9 or 10-inch round tart tin, using the bottom of a drinking glass or measuring cup to tamp down the bottom and square off the sides and corners. Chill the crust in the freezer until ready to fill.

Make sure you have all your ingredients measured out and ready to go. Sprinkle the powdered gelatin evenly over the cool water and allow it to bloom while you prepare the rest of the filling.

In a medium, non-reactive saucepan or other small pot (preferably stainless steel or ceramic) combine the sugar and the lime zest, rubbing the zest into the sugar to release its flavor. Whisk in the eggs and egg yolks until the mixture is totally smooth.

Pour in the lime juice while whisking and transfer to the stove over medium-high heat. Continue whisking almost constantly as the mixture cooks. Once it begins to thicken (the whisk should be leaving trails in the curd) remove from the heat and immediately whisk in the butter until homogenous and glossy.

Strain the mixture through a fine-mesh sieve into a bowl, then stir in the bloomed gelatin until it’s smooth and there are no lumps.

Spread just enough of the raspberry preserves to cover the bottom of the chilled crust.

Gently pour the filling into the crust, shake it slightly to level it off, then tap it gently against the counter and pop the bubbles that come to the surface. Chill the tart in the refrigerator for about 2 to 3 hours or until completely set.

Remove the outer ring of the tin by placing the pan on a can or small bowl and encouraging it to fall from the tart. Top with lime slices and optional whipped cream or meringue and serve.

Topping

Just before serving the tart, make any desired toppings.

For meringue, whisk together the egg whites and sugar in a large bowl if using a hand mixer — or the bowl of a stand mixer fitted with the whisk attachment. In a sauce pan, bring about an inch of water to a simmer and place the bowl over top it (the bottom of the bowl should not touch the water.) Stir the mixture constantly until it’s totally combined, hot and the sugar has dissolved (you can carefully rub some between your fingers to see if any gritty sugar crystals remain.) Remove from the heat and stir in the vanilla. Transfer the bowl to the stand mixer or use your hand mixer, and beat on high until the meringue is thick, fluffy, glossy and holds stiff peaks when the beater is lifted out. Transfer to a piping bag to pipe on decorations or spread it on top using a spoon or offset spatula. Toast the meringue with a kitchen torch, if desired.

For a whipped cream topping: In a medium mixing bowl (ideally stainless steel) vigorously whisk the heavy cream, powdered sugar and vanilla extract until it holds medium peaks when the whisk is lifted out. Pipe or spread on top of the tart.