Place yuzu juice, egg yolk and sugar in a heatproof bowl over a pan of simmering water (double boiler) and cook the curd over medium-high heat whisking constantly. Whisking is important to avoid egg yolks from curdling

After about 8-10 minutes the mixture starts to thicken (mixture will reach around 80C /176F)

Remove from heat, pour the cooked curd through a sieve

With a rubber spatula mix in room temperature butter in small chunks one by one, makes sure each chunk is fully incorporated before adding the next. Hand blend

Let the curd cool before using it as a filling, no need to wait until it fully sets

Sift dry ingredients; flour, icing sugar, salt then add in toasted black sesame seeds

Add very cold butter chunks and rub the mixture between your hands until it becomes a sand like consistency

Add egg into the mixture and mix with your hands just until the dough comes together

Knead with the palm of your hand for a minute or two (do not over knead and do not use mixer) just until the dough becomes smooth

If the dough is too warm and sticky, place it into the fridge for 10-15 minutes first. Otherwise, continue with rolling the dough out into 2mm thickness between two silicone baking mats.

Place the dough into the freezer for 15 min in between the two silicone baking mats. Do not remove the mat at this point

Prepare your oven rack with the perforated "air" baking mat and perforated tart rings on top

Take the dough out from the freezer and using one of the perforated tart rings, cut out 8 circles - this will be the bottom of your tart crust. Carefully move the dough circles with the help of an offset spatula and place them into the rings one by one

Cut 8 long strips out of the dough, this will be the side of the tart

Carefully place the strips into the ring one by one. Press each strip onto the ring so it sticks to it

Place the perforated tart ring with the pastry dough in them into the freezer for 2 hours

Pre-heat oven to 160C / 320F

After 1 hour take the pastry dough with the rings on them out and trim them with a sharp knife

Bake for 20 min then carefully remove the rings and bake for another 5 -10 min until golden brown. Let them cool on the Perforated "air" baking mat before filling

Let tart cases fully cool before filling them

Fill each tart case with the yuzu curd up to the edge

Let the tarts set in the fridge for min 4 hours

To make the chocolate shard: Melt and temper chocolate then color it to black

Spread chocolate over a sheet of parchment paper in a thin and even layer then roll it up

Let it set in the fridge for 60 minutes then carefully start rolling the parchment out. The chocolate should naturally break into shards as you are rolling it out

Store the tartlets in in the fridge