process the respberry and extra sugar in a food processor until smooth. push the puree through a fine-meshed nylon sieve to remove any pips. fold the remaining gelatine into the raspberry mixture. place blobs of cheesecake mixture into the tin and fill the gaps with the raspberry. swirl the two mixtures together,using a skewer or the point of a knife. refrigerate for 4 hours,or until set. can be decorated with whipped cream and raspberries