1 t cornstarch
1 t kosher salt
1/2 c sugar
1 t dry mustard
3 egg
1/2 c white wine vinegar
1 c milk
1 t unsalted butter
whisk cornstarch, salt, sugar, and mustard into eggs
whisk in vinegar and then milk
transfer mixture to the top of a double-boiler
heat and stir until thickened
stir in butter
remove from heat and cool
cover and chill for 2-48 hours
serve slightly chilled
