Pick over the lentils, tip into a sieve and rinse well.
Warm the olive oil in a large saucepan over a medium-low heat and sauté the onion with the thyme and a good pinch of salt until softened and just beginning to turn golden.
Add the garlic and sauté for another minute.
Add the tomato purée, stir, then tip in the stock, bulgur, lentils and paprika.
Stir and bring to a boil.
Reduce to a simmer, cover and cook for 15-20 minutes, until the lentils and bulgur are very soft.
Purée in a food processor or with a stick blender if you prefer a smooth and creamy soup, or leave it as it is, adding a little more stock or water if it is too thick.
Season to taste.
While the soup is cooking, make the flavoured oil.
Warm the olive oil in a pan with the butter until the butter has melted and the foaming subsides.
Remove from heat and stir in the dried mint and paprika.
Serve the soup in warmed bowls with yoghurt and the flavoured oil trickled over the top, and sprinkled with a pinch or two of dried mint.
