In a large pot, add cold water and bring it to a boil over high heat. Once the water is boiling, reduce the heat to medium and add lentils to the pot. Don't cover the pot with a lid. Allow the lentils to simmer for 15 minutes, stirring occasionally. Use a skimmer to clear any foam or impurities that rise to the surface.
While the lentils are boiling, prepare the vegetables. Wash and peel the beets, carrots, mushrooms, and onion. Chop them into small pieces. Peel and mince the garlic cloves.
Preheat the skillet, add a tablespoon of vegetable oil, and reduce the heat to medium. Add the chopped beets and carrots, and simmer them for 5 minutes, stirring well.
Add tomato paste to the sautéed vegetables on the skillet. Mix well. Then, add paprika and dried dill to the mixture and stir until combined. Cover the skillet with a lid and continue to sauté the vegetables over low heat for an additional 10 minutes.
Once the beets and carrots are roasted, transfer them to the pot with boiling lentils. Reduce the heat to medium and add bay leaves to the broth. You may want to cool the skillet and rinse it or use another frying pan to fry onions and mushrooms over medium heat. Add chopped onion, garlic, and mushrooms to the skillet and sauté them until golden. Then, transfer them to the pot with lentils, beets, and carrots.
While the borscht is boiling at a low temperature, wash, peel, and chop potatoes. Then add them to the pot too, and stir the soup well. Continue to cook for another 5 minutes.
Wash the cabbage and remove the tough outer leaves. Then, cut the cabbage in half and slice one half into thin strips using a sharp knife. Now, you can add the sliced cabbage to the soup too. Stir the borscht well again, and continue to simmer over low heat for 5 more minutes.
Add chopped spring onions, chopped fresh dill, and parsley at the end.
Salt and add black pepper to taste.
Turn off the heat and let the borscht sit on the stove for about half and hour. You may want to cover the pot with a towel to keep the warmth.
When serving the borscht, top it with a dollop of sour cream, fresh dill, or parsley. Accompany it with white or dark rye bread, and you can season the bread in Ukrainian style with garlic. Enjoy!