If I could only eat one dessert until the end of time, this would probably be it. I absolutely love the sharp flavour of lemons, and the smooth creaminess of this filling is the perfect compliment. It's impossible to put into words how wonderful these little tarts are, and if you make them they will find a permanant place in your baking repertoire, I guarantee it!
You will need eight 10cm tart tins, or four if you bake the tarts in two batches.
In a stand mixer, beat the butter until just soft. Add the icing sugar & beat again until smooth.
Weigh out the beaten egg, then stir in the salt. Add the egg mixture in two batches, beating well between each addition. Scrape the bowl down to ensure the mixture is smooth and homogenous.
Add the flour, and stir together until mostly incorporated, then tip onto a work surface. Press and squash the dough until it comes together, folding in dry flour as you go.
Split the pastry into two pieces, forming each one into a flat disc, and then wrap in clingfilm.Refrigerate for at least an hour before using.
Cut each disc into four equal pieces, and using a fine dusting of flour, roll each piece into a circle slightly larger than your tart tins. The pastry should be about 3mm thick - about the thickness of a pound coin.
Carefully lift the pastry into the tart tins, and press the pastry into the sides. Do not cut off the excess pastry. Chill the lined tart tins for at least 30 minutes.
Preheat the oven to 175c / 160c fan.
Use a sharp knife to trim off the excess pastry from the top of the tart tins. Push the knife outwards, flush to the top of the tin.
Dock the pastry on the bottom and sides of the tin, using a fork. Line each tart with a square of ovenproof cling-film (I use Cuki Microwave), and then fill with uncooked rice. Fold the excess clingfilm loosely into the middle of the tart.
Bake the tarts blind for 10 minutes, then remove the rice parcels. Bake for another 5-10 minutes until the tart shells are firm and dry, just starting to brown.
Leave the tart shells to cool completely before removing from the tins. Use a microplane zester to smooth any rough edges.
Mix the sugar and lemon zest in a small bowl, and leave to infuse while you prepare the other ingredients.
In a heatproof bowl, add the lemon juice, salt, and eggs. Cube the butter now in preparation for later use.
Set a saucepan of water on the heat and bring to a simmer. Whisk the sugar mixture into the egg mixture, and then place the heatproof bowl on the saucepan to create a bain-marie. Whisk the mixture continuously, until it thickens.
Sieve the mixture into a blender to remove zest and any cooked egg pieces. Turn the blender on, and then add the cold cubed butter, a little at a time.
Pour the lemon cream into your prepared tart shells, and shake gently to bring bubbles to the surface. Use a blowtorch on a low setting to help pop any bubbles on the surface. Transfer the tart to the fridge to set the filling completely.
Whisk the egg whites until frothy and holding their shape a little, then turn the mixer off.
Boil the sugar and water together until they reach 118c.
Continue whisking the egg whites, as you pour the hot syrup down the side of the bowl in a slow and steady stream. Whisk until the meringue become stiff and glossy - about 7 minutes.
Decorate the tart with the Italian meringue as desired. You can use a blowtorch to add colour, as well as definition to your piping.