Add rinsed lentils to the pot; stir well. Pour in vegetable broth and add diced tomatoes (undrained) along with cubed Yukon Gold potatoes and bay leaf.
Bring to a boil, then reduce heat to low. Cover and simmer for 20-25 minutes until lentils and potatoes are tender.
Remove bay leaf; season with salt, pepper, and stir in lemon juice or apple cider vinegar before serving.
Serve hot, garnished with fresh parsley alongside crusty bread or yogurt.