How to Make It
In a large saucepan, heat 1 tablespoon of the olive oil. Add the sausage and cook over moderately high heat, breaking up the meat, until browned and no trace of pink remains, about 5 minutes. Transfer the sausage to a bowl and wipe out the saucepan.
Heat the remaining tablespoon of olive oil in the saucepan. Add the bacon, onion, carrot and garlic and cook over moderately high heat, stirring, until softened, about 5 minutes. Add the lentils, water and bay leaf, season with salt and pepper and bring to a boil. Cover partially and simmer over very low heat until the lentils are tender, about 20 minutes. Discard the bay leaf and stir in the sausage. Season the lentils with salt and pepper and serve.