Cocoa shortcrust tart with chocolate ganache and hazelnuts

A rich, indulgent chocolate-lover's tart, made ahead and refrigerated.
INGREDIENTS FOR A 24 CM TART
COCOA PASTRY
240 g '00' flour
150 g butter
35 g unsweetened cocoa
100 g icing sugar
2 yolks
GANACHE
300 g dark chocolate
280 ml fresh cream
130 g hazelnuts
30 g butter
DECORATION
50 g hazelnuts
50 g sugar
I sift flour, cocoa and icing sugar into a bowl.
I work in butter until crumbly.
I add yolks and knead.
I quickly work on the surface.
Once smooth, I wrap in parchment and refrigerate at least 1 hour.
I roll rested dough into the tin with parchment on the base, leaving a 2 cm rim.
I decorate rim and prick base with a fork; a fluted tart tin works.
I cover with parchment and weights, beans, rice or salt, to blind bake.
I bake at 170°C for 20 minutes, remove weights and paper, bake another 10 minutes and cool.
GANACHE
I heat cream nearly to boiling and add chopped chocolate.
I stir until melted, then emulsify with a stick blender and butter until smooth and glossy.
I add hazelnuts.
I mix well.
I pour into cold pastry shell.
CARAMELISED HAZELNUTS
I melt sugar in a non-stick pan without stirring, moving the pan. Once amber, I add hazelnuts, stir a minute and remove.
I pour onto parchment, set and roughly chop with a knife.
I scatter over tart and refrigerate several hours.
Remove at least 30 minutes before serving.