PREHEAT OVEN 200°C/400°F

Remove dough from fridge, allow to warm 5 minutes if cold and stiff. Butter and dust 9” tart ring with sugar and place on a sheet pan lined with parchment paper. Roll out the dough. Dust dough with flour only if sticky and press into tart ring evenly, with thumbs. Prick all around base of pan with fork to prevent dough from ballooning while cooking. Refrigerator for about 10 minutes. Bake at 200°C/400°F about 10-12 minutes, until just lightly browning, remove and cool 5 minutes before adding the chocolate filling.

TURN OVEN TO 150°C/300°F

For the chocolate filling, melt the chocolate and butter together over steam in a double boiler, stirring to blend. Bring cream to a simmer, beat egg in a separate bowl and slowly pour cream into beaten egg while whisking. Strain if you see any solid egg bits, and mix well with chocolate, then pour into prebaked tart shells, and bake at 150°C/300°F about 15 minutes, just to set. Cool 2 hours before eating, and if storing in fridge, warm to room temperature before eating.

Sprinkle a bit a Fleur de sel crystals on top before serving.