Complex sentence: Natasha's dish was a disaster, as not only her hollandaise broke, it turned into mayonnaise as a result of putting too much vinegar in it; also, one of her poached eggs broke, leaking yolk all over the plate.
Split into simpler sentences: Natasha's dish was a disaster, as not only her hollandaise broke, it turned into mayonnaise as a result of putting too much vinegar in it. Also, one of her poached eggs broke, leaking yolk all over the plate.