Soak the lentils in plenty of cold water overnight. Drain the water the next day. Lard the peeled onion with the bay leaf and the two cloves.
Heat the oil in a large saucepan. Briefly sweat the finely diced paprika, carrots and tomatoes as well as the pressed garlic cloves in it. Stir in both types of paprika and the cumin. Add the lentils and the peppered onion, pour 1 1/4 l fresh water and add the granulated vegetable stock. Bring everything to the boil and simmer over a low heat for 20 minutes.
Add the diced potatoes and simmer for another 15 minutes. Remove the onion and season the stew with salt, pepper and possibly a little vegetable stock. This goes well with white bread and a strong Spanish red wine, e.g., from Navarre.
In the original recipe, meat broth is used and 5 minutes before the end of the cooking time, 500 g of sliced chorizo (Spanish paprika sausage) are added. A ham bone can also be cooked with the lentils.