1
Place the lentils in a large saucepan, cover with the water or stock, and bring to a boil. Lower the heat and simmer gently until tender, at least 35 minutes or so. (The exact timing will depend on the type and age of the lentils.) Drain well.
2
Heat 2 tablespoons of the oil in a skillet over medium heat, add the onion and saute just until softened and pale golden, about 10 minutes. Add the garlic and cook for 2 minutes more. Add the butter, the remaining oil, and the mushrooms and saute until the mushrooms are tender. Season with salt and pepper. Add the lentils, the 3 tablespoons of chopped parsley, lemon juice, salt, and pepper and heat, stirring, just until warmed through. Remove and discard the garlic. Taste and season the lentils accordingly with more lemon juice, salt, and pepper.
3
Meanwhile, in a separate skillet, fry the bacon until crisp.
4
Sprinkle the lentils with the parsley and bacon, left whole or crumbled into pieces, the more the better.
