Nothing screams summer like a good citrus tart, and this is a great one. Now it takes a little time, and a little patience to get this one right, but it’s worth the effort. The tart shell and the lemon and lime filling are the easy parts. Just remember slow and steady when you are thickening the curd, too much heat and you will have citrus scramble eggs. And never stop stirring.
The Italian meringue can be tricky. If you don’t have a sugar thermometer (I don’t, and still manage) there is a way to tell when the sugar is at the right consistency. First wait until the sugar has dissolved, you can stir up until this point, but after this no stirring allowed. Then, on a medium high heat boil the sugar for about 10 minutes, you will notices the bubbles on the top of the mixture starting to get bigger, and hold their shape better (as if they are slowing down), at this point the sugar is ready to combine with the partially whipped egg whites. Try not to get the sugar syrup on the whisk, as it will solidify, and you will end up with a grainy texture. Now the rest is in your hands. Enjoy 🙂
2 large lemons
115 g butter, at room temperature
340 g sugar
4 large eggs
¼ tsp salt
145 g unsalted butter, plus more for greasing, at room temperature
110 g sugar
245 g plain flour
1/2 tsp pure vanilla essence
For the Italian Chantilly
150 g sugar
60 ml water
60 g egg whites (2 eggs)
½ sheet gelatin
150 ml chilled whipped cream
For the tart shell
Mix the butter and sugar together in the bowl of an electric mixer fitted with a paddle attachment until they are just combined. Add the vanilla. In a medium bowl, sift together the flour and salt, then add them to the butter mixture. Mix on low speed until the dough starts to come together.
Shape the dough into a flat disk. Press pastry into a 25cm round pie tin, making sure that the finished edge is flat. Chill in the freezer until firm.
Meanwhile, preheat the oven to 180°C.Place a piece of parchment paper over the pie shell and fill with dried beans or rice.
Bake for 20 minutes. Remove the paper and beans, prick the tart all over with a fork, and brush with egg yolk. Bake for 20 to 25 minutes more, or until lightly browned. Allow to cool to room temperature.
For the filling
Remove the zest of the lemons and limes with a zester, being careful to avoid the white pith. Squeeze the fruits to make 125ml of juice and set the juice aside.
Add the sugar to the zest and process for 2 to 3 minutes, until the zest is very finely minced.
In a bowl, cream the butter with the sugar and lemon zest. Add the eggs, one at a time, and then add the lemon and lime juice and salt. Mix until combined.
Pour the mixture into a medium saucepan and cook over low heat, stirring constantly, until thickened, about 10 minutes. The lemon curd will thicken at about 68°C or just below a simmer. Remove from the heat.
Fill the tart shell with the warm lemon curd and allow to set at room temperature.
For the Italian meringue Chantilly
In a medium saucepan, combine the sugar and water and place on a medium heat. Stir occasionally until the sugar dissolves. Bring the temperature up to a boil.
In the meantime, whip up the egg whites until they are almost able to hold their shape. Place the gelatin in some cold water to soften.
Once the sugar has reached 116 C, remove from the heat, and slowly pour into the egg whites, whisking all the time. Once you have added all the sugar syrup, squeeze out the excess water from the gelatin and put it into the egg white mixture. Whisk constantly for about 7 minutes, or until the bottom of the mixing bowl is no longer hot.
Fold the meringue into the whipped cream and immediately place on top of the lemon tart. Chill for two hours before serving.