2 cups half-and-half
1 cup whipping cream
1/2 cup sugar
1/2 cup peach preserves (not jelly)
1 vanilla bean, split and scraped
Pinch kosher salt
4 medium peaches, halved, seeded and grilled or broiled until brown
If you do not have a thermometer, bring the mixture just barely to a simmer. As soon as you see a bubble on the surface, remove it from the heat.