How-to Test & Cool Stirred Custards
To test a stirred custard for doneness, dip a metal spoon into the hot mixture. If the custard coats the back of the spoon, it is sufficiently cooked. If too thin, continue to cook.
Chill stirred custard quickly by placing the pan in a large bowl or sink of ice water. Stir for several minutes or until no longer hot. Proceed with recipe as directed.