Rinse split peas in a sieve.

Boil water with peas, gammon, and bacon.

Skim off any scum.

Pour off water, rinse peas and meat, add fresh water.

Gently cook peas and meat.

Peel and dice celeriac and potatoes.

Peel and dice carrot.

Cut and wash leeks.

Add vegetables to the pan and simmer until peas are broken (1.5-2 hours).

Remove meat from the pan.

Remove rind and bones from meat.

Cut meat into small pieces and return to the pan.

Wash and chop celery leaves.

Add smoked sausage and celery 20 minutes before the end of cooking.

Taste, season with pepper and salt.

Cool the soup completely.

Reheat the soup gently before serving.

For freezing, add smoked sausage during reheating or divide equally into portions.