Blitz the sesame seeds in a food processor to turn into smaller pieces (but not powder).
Combine the butter, icing sugar, salt and lemon zest until creamy (using a stand mixer or food processor).
Add in the black sesame seeds and the egg and mix until combined. Add the flour and mix until it just about comes together.
Press into a flat square, cover in cling film and chill for 1 hour.
Roll out dough to 2-3mm (⅛ inch) thickness. Using a 25cm (10 inch) tart ring, cut out a large circle for the base. Cut out long strips of dough and line edge of the tart ring. Press gently with your fingers at the seam to attach the edges of dough.
Chill tart for 30 minutes, then cut out the excess with a sharp knife.
Pistachio, honey & lemon frangipane
To make the pistachio paste, soak raw shelled pistachios for 1 hour in water. Remove skin, then place the pistachio kernels in a blender and mix until they form a paste. The paste can be prepared in advance.
Mix the butter, sugar, salt and pistachio paste. Beat until pale and fluffy.
Add the honey, lemon juice and zest and mix well. Slowly beat in the eggs, one at a time. Mix in the flour and almond flour until creamy.
Place in a piping bag and pipe mixture into the chilled (unbaked) tart crust. The frangipane will come up to less than half of the height of the tart crust. Any leftover mixture can be baked separately.
Evenly sprinkle the pistachios over the frangipane and gently press them down with your thumb.
Bake for 15-20 minutes or until the frangipane is golden-brown in colour.
Let the frangipane cool for 1 hour before adding the ganache.
Blackberry ganache
To make the puree, place fresh (or frozen) blackberries in a saucepan and heat over low-medium fire.
Crush using a spoon until you obtain a smooth paste. Sieve to remove seeds.
Melt the chocolate in the microwave in short bursts of 10-15 seconds, mixing after each burst to prevent it from burning.
Once melted, add the heavy cream and lemon juice. The mixture will thicken, but don't worry. Pour the hot puree over the chocolate mixture.
Combine all ingredients using spatula until the mixture is smooth and glossy. Mix with immersion mixer to get it silky smooth, but without adding air bubbles.
Pour over the cooled frangipane, ensuring the surface is smooth.
Chill in the fridge for 2 hours before decorating.
Decorating the tart
To decorate, melt some white chocolate or white candy melts in the microwave in short bursts of 10-15 seconds.
Place chocolate in piping bag fitted with a thin round nozzle.
Pipe long transversal lines from one side to the other, intersecting the lines in the middle of the tart.
Start piping a spiral starting from the middle of the tart. Continue with individual lines connecting each transversal line to the neighbouring one - please see diagram in article body for more details.
Add small droplets of chocolate to mimic water droplets if needed.
Notes
I recommend using a kitchen scale in grams for more accuracy. The cups used for the conversion are standard US customary cups (1 cup flour = 136g). There are many different types of cups across the globe, which is why I strongly recommend using grams instead.