very simple indeed. i’ve been making this for 30 years or more. i prefer brown lentils though. it’s also nice with cannelini or butter beans which of course require more soaking and cooking.
i also like to marinate the onions along with the lentils/beans just don’t add them while it’s all very hot.
another variation would be to add lemon juice/vinegar to the marinate after it’s all cooled down somewhat.