In a large pot, heat the olive oil over medium heat. Add the diced onion and sauté for about 5 minutes until translucent.
Stir in the minced garlic, diced carrots, and celery. Cook for an additional 5 minutes, stirring occasionally.
Add the sliced mushrooms to the pot and sauté until they release their moisture and begin to brown, about 6-7 minutes.
Stir in the rinsed lentils, diced tomatoes (with juice), vegetable broth, soy sauce, thyme, smoked paprika, salt, and pepper. Bring the mixture to a boil.
Reduce the heat to low and cover the pot. Let the stew simmer for about 30-35 minutes or until the lentils are tender. Stir occasionally to prevent sticking.
Taste and adjust seasoning as needed. If the stew is too thick, add a little more vegetable broth or water to reach your desired consistency.
Once done, remove from heat and let it sit for 5 minutes before serving.
Notes
Serve the stew in deep bowls and garnish with freshly chopped parsley. Pair it with crusty bread for a complete meal.