I've been making homemade mayonnaise for the past month or so now: whole egg, mustard, salt, other seasonings ad lib, vinegar, 1 2/3 cups peanut oil, apply Bamix.

It sets up beautifully in less than a minute, but after 2 to 3 days in the fridge, it "wilts" and gets runny. Still rich and flavorful—my husband is happy to pour it on fresh-cooked fish—but useless for sandwiches and bad for the kitchen cred.

What am I doing wrong?

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