Put the lentils in boiling water and cook according to the instructions on the package. Peel the carrot, wash the celery and, if necessary, pull the strings. Cut both vegetables into small cubes and cook with the lentils for the last 6-8 minutes.
Peel the onions, cut in half lengthways and cut into thin strips. Heat the oil in a pan and fry the onion strips until translucent. Add the stock, vinegar and honey, bring to the boil and season well with salt, pepper and paprika powder. Wash the parsley and shake well dry, cut the leaves into small pieces and add to the dressing.
Drain the lentils with the vegetables in a sieve, rinse briefly and mix with the hot dressing. Let it steep for 10 minutes or longer. Before serving, season the salad again with salt and pepper and spread on spoons.