Cook pasta al dente. Place the red lentils in a saucepan with salted water and add a pinch of coriander. Be careful, the lentils easily overcook! Cook for 5-10 minutes until the lentils are soft. Sauté the diced onions in a pan until translucent. Add the cream and sour cream, bring to the boil. Add the drained lentils, season everything again with the remaining spices, fold in the pasta.