In a large saucepan, whisk together sugar, cornstarch, and salt.

Gradually whisk in milk and whipping cream.

Cook over medium heat, stirring constantly, until slightly thickened (10-12 minutes).

Remove from heat.

Whisk egg yolk until slightly thickened.

Gradually whisk about 1 cup of the hot cream mixture into the yolk.

Add the yolk mixture to the remaining cream mixture, whisking constantly.

Whisk in vanilla bean paste.

Cool for 1 hour, stirring occasionally.

Meanwhile, cook peaches and corn syrup in a small saucepan over medium heat, stirring often, for 4-5 minutes.

Coarsely mash the peach mixture and let cool for 30 minutes.

Stir the peach mixture into the cooled cream mixture.

Place plastic wrap directly on the cream mixture and chill for 8-24 hours.

Melt butter in a small skillet over medium heat.

Add pecans and cook, stirring constantly, for 8-9 minutes, or until toasted and fragrant.

Remove from heat and sprinkle with kosher salt.

Cool completely (about 30 minutes).

Pour the chilled cream mixture into the freezer container of a 1 1/2 quart electric ice cream maker.

Freeze according to the manufacturer's instructions.

Before transferring the ice cream to an airtight container, stir in the pecan mixture.

Freeze further as needed.