Heat a large pot over low medium heat. Once hot, add the oil, onion, and carrots. Cook for about 15 minutes, stirring occasionally, until softened and the onions are translucent. Reduce the heat if the vegetables start to stick.
2 teaspoons oil, 1 medium onion, 2 medium carrots
Add the potatoes, garlic, and tomato paste. Cook for another five minutes, stirring once or twice. The tomato paste should darken and look a little brown.
2 medium potatoes, 2 cloves garlic, 1 tablespoon tomato paste
Stir in the paprika and oregano, then add the canned tomatoes, vegetable broth, and lentils. Season with salt and pepper.
1 teaspoon sweet paprika, 1 teaspoon dried oregano, 2 teaspoons sea salt, ½ teaspoon black pepper, 150 grams (1 cup) brown lentils, 400 grams (13.5 oz.) canned diced tomatoes, 800 ml (3 ¼ cups) vegetable broth
Increase the heat to bring the soup to a low boil, then reduce the heat to a high simmer, covered, for about 20 minutes. The soup is ready once the lentils are softened.
Taste the soup and adjust seasoning as needed, then serve hot. Keep leftovers in the refrigerator for up to five days or freeze up to three months.