The following recipe gives the method for preparing vanilla custard sauce, or crème anglaise. Special care is necessary in preparing this sauce because the eggs can curdle easily if overcooked. The following guidelines will help you succeed:
Use clean, sanitized equipment, and follow strict sanitation procedures. Egg mixtures are good breeding grounds for bacteria that cause food poisoning.
When combining the egg yolks and sugar, whip the mixture as soon as the sugar is added. Letting sugar and egg yolks stand together without mixing creates lumps that cannot be beaten out (Figure 36.1). Using a stainless-steel bowl for this step makes the cooking and stirring easier in step 5.
Heat the milk to scalding (just below simmering) before combining with the egg yolks. This makes the final cooking much shorter. To avoid scorching, you can set the pan of milk in a pan of boiling water. This takes longer than using direct heat, but the pan can be left unattended for a few minutes while you perform other tasks.
Slowly beat the hot milk into the beaten eggs and sugar. This raises the temperature of the eggs gradually and helps prevent curdling.
Set the bowl containing the egg mixture in a pan of simmering water and stir constantly to prevent curdling.
To test for doneness, two methods are available. Keep in mind that this is a very light sauce, so you can’t expect a lot of thickening.
Check the temperature with a thermometer. When it reaches 185°F (85°C), the sauce is cooked. Never let the temperature go above 190°F (87°C), or the sauce is likely to curdle.
When the mixture lightly coats the back of a spoon instead of running off like milk, the sauce is cooked (Figure 36.2).
Immediately cool the sauce by setting the pan or bowl in ice water. Stir occasionally to cool it evenly.
If the sauce curdles (Figure 36.3), it is sometimes possible to save it. Immediately stir in 1–2 ounces (30–60 mL) cold milk, transfer the sauce to a blender, and blend at high speed.