How to Fix Broken or Split Sauce: Rescue Techniques
Quick take: Broken sauces can often be rescued with temperature control, fat addition, or emulsification.
For broken emulsions (hollandaise, mayonnaise): Whisk vigorously while adding the separated liquid drop by drop. For hollandaise, place over warm water and whisk in a teaspoon of warm water slowly.
For split cream sauces: Remove from heat. Add ice cubes and whisk vigorously—rapid cooling often reunites the emulsion. Or blend in a food processor for 10-15 seconds.
For grainy custards: Strain through fine mesh, then process in a blender with a tablespoon of cold cream.
Prevention: Add fat slowly to emulsions, keep heat moderate, and always temper eggs before adding to hot liquids.