Heat 1 tablespoon of the olive oil in a large pan, then add the sausages and cook until browned all over. Remove the sausages from the pan and set aside.Add the remaining oil to the same pan, stir in the onion and cook until tender and lightly coloured. Stir in the ginger and garlic and cook until the aroma rises. Then stir in the spices and tomato puree and cook for 2 minutes longer. Add the chopped tomatoes and cook for a few minutes, until softened.Return the sausages to the pan and stir in the chestnuts, lentils and chicken stock. Bring to a simmer and cook gently for 20 minutes, until the lentils are tender and the sausages are cooked through. If the mixture gets too dry, add a little more stock or some water.Season with plenty of salt and pepper, and mix in the coriander to serve.
The perfect accompaniment - a glass of Crozes Hermitage