Custard Pudding No. 2

Heating the custard in a double boiler (bain-marie) prevents direct heat contact, keeping temperatures below 185°F where eggs would scramble. The small amount of flour acts as insurance, providing starch molecules that interfere with egg protein bonding and creating a more stable, forgiving custard. Constant stirring distributes heat evenly and prevents protein coagulation in hot spots, while cooling with continued stirring stops carryover cooking that could curdle the mixture.