1. Put the flour in a mixing bowl and make a well in the centre. Crack the egg into the middle and pour in about 50ml (2fl oz) of milk and half the oil. Start whisking from the centre, gradually drawing the flour into the egg, milk, 1 tsp of oil and the vanilla. Once all the flour is mixed in, beat until you have a smooth, thick paste.
2. And a good splash of milk and whisk to loosen the batter. Still whisking, pour in the remaining milk until you have a batter the consistency of single cream.
3. Heat a small frying pan over a moderate heat and wipe with oiled paper. Ladle some batter into the pan, tilting the pan to move the mixture over the base in an even layer. Leave to cook for 30 seconds. Flip over and cook for a further 30 seconds.
4. Continue with the rest of the batter oiling between each one. Stack the crepes onto a plate. Keep warm in a low oven, or freeze for future use.
5. Beat together the custard and the yoghurt with the cinnamon. Serve the crepes with plenty of berries and a spoonful of cinnamon custard. Dust very lightly with icing sugar.