To make the caramel, heat the sugar and water in a heavy-based pan until the sugar dissolves, stirring occasionally. Once the sugar has dissolved, stop stirring and cook until the sugar syrup caramelises and turns a deep golden brown. Swirl the liquid in the pan occasionally so that it doesn’t burn.
As soon as the caramel is ready, pour it carefully into a 1.5 litre/2¾ pint non-stick ridged flan tin. (Do not use a loose-bottomed flan tin for this) Holding the tin with an oven cloth, tip the caramel up into the ridges – be very careful as the caramel will be extremely hot! Leave to one side while the caramel sets.
To make the custard, pour the milk into a medium non-stick saucepan and add the honey and orange zest. Bring to a simmer and cook until the honey dissolves, stirring occasionally. Watch carefully so that it doesn’t boil over. Remove the milk from the heat and leave to infuse for 10 minutes.
Meanwhile, bring a kettle of water to the boil and preheat the oven to 170C/325F/Gas 3½. Put the flan tin into a roasting tin.
Whisk the eggs and wine together until pale and creamy. Strain the hot milk and honey through a fine sieve into a jug, then pour on to the eggs and wine, stirring constantly. Pour this mixture into the flan tin on top of the caramel.
Pour just-boiled water into the roasting tin to come halfway up the sides of the flan tin. This helps the custard cook gently and gives a smooth texture to the finished flan.
Bake for 45–50 minutes or until the custard is just set. Cover the tin loosely with foil halfway through the cooking time to prevent the top browning too much. The custard should still be fairly wobbly in the centre when it is cooked and will continue to set as it cools.
Take the roasting tin out of the oven and leave the flan to cool in the water for at least an hour. Once cooled, cover with cling film and transfer to the fridge. Chill for at least 6 hours or overnight.
To serve, press the custard all the way around with your finger tip to break the seal at the edge of the tin. Place a fairly deep serving plate on top of the tin (to contain the caramel) and invert. Holding both the plate and flan tin tightly together, give a small shake. The custard should then drop down on to the plate. Pour any caramel in the dish over the custard. If the custard is reluctant to leave the tin, dip the base very quickly into a bowl of just-boiled water and try again.