makes 1½ pints; adapted from David Lebovitz's Fleur de Lait in The Perfect Scoop and Serious Eats' Fior de Latte
Measure milk and cream into a 4-cup glass measure. Pour half into saucepan and add the sugar, cornstarch, and pinch of salt. Whisk to combine and set pan over moderate heat. Cook, whisking constantly, until mixture begins to bubble and thicken. Lower heat to maintain a gentle rather than vigorous bubbling, continue whisking a couple minutes to cook the starch, preventing a raw flavor. The whole process will take about 5 minutes.
Add reserved milk and cream to the cooked mixture. Whisk to combine and pour back into the 4-cup measure. Cool slightly and press a piece of plastic wrap to the surface to prevent a skin from forming. Refrigerate overnight then freeze in ice cream maker.