1In a small bowl, mash the raspberries with a spoonful or two of the sugar with a fork. In another bowl, stir together the creams and milk, sugar and vanilla. Freeze in an ice cream maker according to the manufacturer’s directions. When it gets thick and is frozen but still soft, pour in the raspberry puree. Let it go until it's swirly, or wait longer until the whole mixture is pale pink.
2Serve immediately or if you want it firmer, transfer to a container or bowl and put it in the freezer until firm.