Instructions

• Preheat the oven to 160°C/320°F (fan).
• Make the caramel: place a medium saucepan over medium–low heat. Add the 300 g granulated sugar in batches, stirring slowly with a wooden spoon until it melts and becomes a dark caramel. Gradually and carefully pour in the 600 g heavy cream while stirring continuously. Bring to a gentle simmer and cook for 8–10 minutes, stirring occasionally. Remove from the heat, add the 100 g cold diced butter and the 2 pinches of salt, stirring until smooth. Transfer to a bowl and let cool to room temperature until thickened but still pourable.
• Make the dough: in a large bowl combine 240 g sifted all-purpose flour, 1 pinch of salt, 150 g cold diced butter, 70 g powdered sugar, and 1 g baking powder. Rub the butter into the dry ingredients with your hands (or a pastry cutter) until the mixture resembles coarse crumbs.
• Add 1 medium egg yolk to the crumb mixture and knead just until it forms a pliable dough. If the dough is too dry or won’t come together, add up to 2 tbsp water, 1 tbsp at a time, until it binds. Shape the dough into a disc, wrap in plastic wrap, and refrigerate for 1 hour.
• Roll and line the pan: place two sheets of parchment paper on your work surface and lightly dust with flour. Roll the chilled dough between the sheets to an even thickness large enough to line a rectangular 30 × 12 cm (12 × 5 in) cake pan. Remove the top parchment, transfer the dough to the pan, press it firmly into the bottom and up the sides, and trim any excess. Prick the base all over with a fork.
• Blind bake: line the dough with parchment and fill with baking beans or other pie weights. Bake at 160°C/320°F (fan) for 20 minutes. Remove from the oven, lift out the parchment and beans, and set aside the pan.
• Egg wash and finish baking: beat the remaining 1 medium egg yolk with a little water, then brush it over the tart surface. Increase the oven temperature to 180°C/356°F (fan) and return the tart to the oven. Bake until the crust is golden brown (about 8–12 minutes). Remove from the oven and let the crust cool completely in the pan.
• Make the ganache: heat 150 g heavy cream in a small saucepan until it just begins to boil. Remove from heat, add the 300 g chopped dark chocolate, and stir until smooth. Set aside to cool slightly.
• Assemble the tart: carefully unmold the cooled tart shell and place it on a serving plate. Pour the cooled caramel into the shell, spreading it evenly. Pour the chocolate ganache over the caramel and smooth the top.
• Finish and set: sprinkle chopped hazelnuts, pomegranate seeds, and a little coarse salt over the top as desired. Refrigerate the assembled tart for 2 hours to set.
• Slice and serve.