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What ingredients are using? It's not mayonnaise really if you are not using eggs somehow. A tablespoon of mustard will help emulsify oil but what are we missing here?
I'm guessing she is following this recipe:
I believe this recipe is counting on the lecithin in the milk to act as the emulsifier.
I second the idea of using mustard as the emulsifier. I'd probably start with a teaspoon.
worked!!! thank you so much!