Peel and finely chop the onion. Halve the pepper. Scoop out the seeds and white bits, then finely chop it. Warm a large pan over a low heat for 1 min. Add 1 tbsp olive oil, the onion and pepper. Season with salt and pepper. Cover and sweat for 5 mins.

Peel and crush the garlic. Rinse the red lentils under cold running water. Stir the garlic into the veg. Cook and stir for 1 min till the pan smells sweet and aromatic. Stir in the vinegar, then add the lentils and tomatoes.

Add 500ml boiling water to the pan. Cover, turn up the heat and bring to the boil. Turn the heat down a little and simmer for 20 mins. Taste and add more salt and pepper if you think it needs it. Ladle into warm bowls. Garnish with parsley leaves to serve.