Soak lentils overnight. Rinse and drain.
Finely chop onion, garlic, and carrot.
Heat oil in a large saucepan over medium heat. Add onion, garlic, and carrot. Cook for 3-4 min until softened.
Add cumin, paprika, and thyme. Cook for 1 min, stirring, until fragrant.
Add lentils and remaining ingredients. Bring to the boil, then reduce heat to low. Cover loosely and simmer for 40 min, stirring occasionally.
Check lentils for tenderness. If still firm, cook a further 10-15 min, adding a splash more liquid if needed.
Remove bay leaf. Stir through vinegar and butter. Taste and adjust seasoning before serving.
Serve topped with chopped parsley and with some vinegar for everyone to stir through to taste.