Recipe for a salad

To make this condiment your poet begsThe pounded yellow of two hard boiled eggs;Two boiled potatoes, passed through kitchen sieve,Smoothness and softness to the salad give;Let onion atoms lurk within the bowl,And, half suspected, animate the whole;Of mordant mustard add a single spoon,Distrust the condiment that bites so soon;But deem it not, thou man of