Chocolate Raspberry Ice cream

3 Tbsp unsweetened cocoa powder -- sieved
600 ml milk
125 g caster sugar
1 tsp vanilla extract -- or
2 tsp vanilla essence
125g raspberries
grated rind and juice of half a lemon sugar to taste

Blend the cocoa to a thin paste with a little of the cold milk. Heat the
remaining milk with the sugar until the sugar has dissolved and the milk is
almost boiling. Add the hot milk to the cocoa, stirring all the time.
Flavour with the vanilla, then leave until completely cold.
Whizz the raspberries with the lemon rind and juice in a food processor,
and add sufficient sugar to sweeten them to taste. Rub the puree through a
sieve, if you wish, then chill it until required.
Turn the chocolate milk into the ice-cream machine and freeze-churn until
ready to serve. Remove the dasher from the machine, pressing the ice milk
back into the machine. Make some holes in the ice milk, using a thick
skewer or a thin spoon handle, and fill with the raspberry puree. Leave for
a few minutes, then scoop out the ice milk across the puree, creating a
ripple effect. Alternatively, drizzle the puree over the chocolate ice milk
as you scoop it.