1  medium beet, peeled, grated
2 tablespoons apple cider vinegar
5 tablespoons vegetable oil, divided
1  medium onion, chopped
2  large carrots, chopped
1/2  medium head cabbage, cut into slivers
20  whole peppercorns
2 1/2 teaspoons salt, divided
1 to 1 1/2 pounds boiling potatoes, peeled and cut in 1-inch chunks
2  medium tomatoes, chopped (optional)
4 large  bay leaves
1/3 cup chopped fresh dill
1/3 cup chopped fresh parsley
some  minced garlic to taste

Bring a large pot of water to boil over high heat. Meanwhile, put the beets in a medium skillet over medium-high heat. Add the apple cider vinegar and 2 tablespoons of oil. Cover and sauté stirring occasionally, until beets redden and are tender, about 10 minutes. Remove from heat and set aside.

In large skillet, heat the remaining 3 tablespoons of oil over medium-high heat. Add the onions and carrots; cook, uncovered, stirring occasionally, until carrots are tender and onions are beginning to brown, 12-14 minutes. Remove from heat and set aside.

When water in the pot boils, add the cabbage, reduce heat to medium-high, and add the peppercorns and 2 teaspoons of the salt. Cook until cabbage is just tender, 8-10 minutes. Add potatoes; cook until just tender, 15-20 minutes.

Add beet mixture. When the soup returns to a boil, add carrot-onion mixture, tomatoes, bay leaves, and the remaining 1/2 teaspoon salt. Cook until tomato is soft, 7-8 minutes. If not using tomato, cook until soup is piping hot, 4-5 minutes. Remove from heat.

Stir in the dill, parsley, and garlic to taste. Let soup stand for at least 15-20 minutes to let the flavor develop.