Wash, peel, and chop all vegetables into bite-sized pieces.
Add lentils, carrots, celery, onion, garlic, potatoes, zucchini, bell pepper, and diced tomatoes to the crock pot.
Stir in thyme, smoked paprika, cumin, bay leaf, salt, and pepper. Drizzle with olive oil.
Pour in the vegetable broth, ensuring everything is covered. Stir gently.
Cover and cook on low for 6–8 hours or on high for 3–4 hours, until the lentils and vegetables are tender.
Remove the bay leaf, taste, and adjust seasoning if needed.
Ladle the stew into bowls, garnish with fresh parsley, and enjoy warm with crusty bread.