Put the lentils in a frying pan and cover with cold water. Bring to the boil once, then pour off into a sieve and drain.
Remove the skin from the onion and chop finely. In a medium frying pan, heat the olive oil. Sauté the onion and cumin in it. Add the long grain rice and lentils and sauté briefly. Extinguish with the white wine and stir to absorb from the long grain rice. Then add the soup and let the long grain rice swell for 40 to 45 minutes with a closed lid on a low fire, stirring occasionally.
In the meantime, rinse the spinach thoroughly. Blanch in boiling hot salted water for just under a minute. Drain and squeeze very well. Defrost frozen spinach and squeeze well.
For the sauce, remove the peel from the onion and garlic and chop finely. Cut pepperoncino in half lengthwise, remove seeds and cut into fine strips. Sauté everything in olive oil. Add the pelati tomatoes, season with salt and pepper and simmer, half-covered, for about 15 minutes.
About five minutes before the end of the cooking time, loosely mix the spinach with the long grain rice and cook with the lid on. Season with salt and pepper. Serve the tomato sauce separately.
Tip: Did you know that one bowl of spinach already covers the entire daily requirement of vitamin K and beta-carotene?