Stir milk, cream, and sugar in a medium saucepan over medium-high heat until mixture comes to a rolling boil (it may look curdled, but this is normal). Meanwhile, whisk yolks, sugar, and salt in a medium bowl until mixture is pale yellow and sugar dissolves.

Place a medium metal bowl in a large bowl of ice water; set a fine-mesh sieve over metal bowl. Whisking yolk mixture constantly, gradually add hot cream mixture (to prevent the eggs in the yolk mixture from scrambling). Return to pan. Stir custard over low heat until thick enough to coat the back of a spoon, about 2 minutes.

Immediately strain custard into metal bowl. Let custard cool completely, stirring often. tir Big Peach and vanilla into custard. Add more Big Peach to taste by teaspoonfuls, if desired. Custard can be made 1 day ahead. Cover and chill.

Process custard in an ice cream maker according to manufacturer's instructions.

Transfer ice cream to an airtight container, cover, and freeze. Ice cream can be made 3 days ahead.

ALTERNATE PLAN [OR PLAN B] Make your favorite vanilla ice cream and add Big Peach instead of vanilla and some of the milk. Add the pureed peaches and freeze.