This year, before you step into the kitchen to wield your holiday whisk, consider brushing up on a few kitchen science fundamentals. By: Lisa Bell & Nicole Rees
Heating a creamy custard over an intense flame can scramble the eggs, and light custards made with milk are even more fragile because milk is less stable than cream. If you add sugar or any acidic ingredients to milk as it heats, it's almost sure to curdle. To keep things smooth and silky, combine sugar, egg yolks, and any flavorings separately, and gradually add hot milk to the mixture so eggs can slowly come up to the proper temperature (also called tempering), stirring the mixture constantly with a whisk.