For the pastry, add all the ingredients into a food processor, add pulse until combined. Turn out onto a lightly floured surface and roll out and use to line a 20cm tart tin. Prick the base with a fork, then chill for 20 minutes.
Preheat oven to 200 C / 180 C fan. Line the pastry case with baking paper then add baking beans. Put the case onto the oven and blind bake for 10 minutes. Remove the baking paper and beans, then return to the oven for 5-6 minutes or until the base of the case is dry and cooked through. Remove the case and leave to cool.
Put the cream and honey into a medium sized saucepan and heat gently until scalding point. Turn off the heat then add the butter, zest and chocolate. Stir until fully melted and well combined. Pour the filling into the tart case and set aside in the fridge to set for a minimum of 4 hours.
Thinly slice one of the clementines and arrange on a heat proof surface. Sprinkle the slices with the caster sugar and caramelise using a blow torch. Arrange on top of the filling, overlapping the slices to they look fanned slightly then finely grate over the zest of the remaining clementine before serving.