Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium heat.
Add the onion, carrots, and celery; sauté for approximately 7 minutes until the onions are translucent and vegetables begin to soften.
Add the sliced mushrooms to the pot and cook for 8-10 minutes until they have released their moisture and turned golden brown.
Stir in the minced garlic, dried thyme, and smoked paprika; cook for 60 seconds until fragrant.
Add the rinsed lentils, vegetable broth, crushed tomatoes, bay leaves, and tamari; stir to combine.
Bring the mixture to a boil, then reduce the heat to low, cover partially, and simmer for 30-35 minutes or until the lentils are tender.
Remove and discard the bay leaves.
Stir in the chopped kale and lemon juice; continue to cook for 3 minutes until the kale is wilted.
Season with salt and black pepper to taste and serve hot.