In a large pot, heat olive oil over medium heat. Add chopped onions and sauté until they are translucent, about 5 minutes.
Stir in minced garlic, carrots, and celery. Cook for another 5 minutes until the vegetables start to soften.
Add the diced potatoes to the pot and mix well with the other vegetables.
Sprinkle in the cumin, smoked paprika, salt, and pepper. Stir everything to coat the vegetables with the spices.
Pour in the rinsed lentils and vegetable broth. Add the bay leaf and bring the mixture to a boil.
Once boiling, reduce the heat to low and simmer uncovered for about 30 minutes, or until the lentils and potatoes are tender. If the soup becomes too thick, you can add more broth or water to reach your desired consistency.
Remove the bay leaf before serving. Taste and adjust the seasoning if needed.
Ladle the soup into bowls and garnish with fresh chopped parsley.
Notes
Adjust seasoning to taste and add more broth if the soup is too thick.