Raspberries and peaches are a natural summertime duo, and they marry to delicious effect in this rich ice cream. If peaches aren't in season, this ice cream is also great as just plain raspberry! If you like a bit of texture in your ice cream, cut one of the peaches into small, bite-sized cubes and add them to the ice cream base once it has started churning.
Purée the raspberries in a food mill or food processor, then strain through a fine mesh sieve, discarding the seeds. Next purée the peaches and add the peach purée to the raspberry purée, stirring to blend. Refrigerate until cold.
Place the milk and cream in a heavy-bottomed saucepan and bring to a boil over medium-high heat.
Meanwhile, in a large metal or glass bowl, whisk the egg yolks with the sugar, vanilla, and salt. Slowly add the hot milk mixture to the eggs, whisking constantly. Let this mixture (the "ice cream base") cool at room temperature for 10 minutes, then refrigerate until it's completely chilled. Once cold, add the raspberry-peach purée to the base and stir to combine.
Add the mixture to your ice cream maker and freeze according to the manufacturer's directions.