depends on the type of lentil, but i've had luck with some types of lentils cooked on the "rice" setting in my pressure cooker - they come out tender but still have their shape, making them great for bean burgers or chilled with lime and fresh herbs for a lentil salad. if you're struggling with the cook times, you can cook them to death so they disintegrate and become a creamy soup (havent tried it yet, but I'm planning to make this lentil soup this weekend), and personally, i really like them stewed (overcooked) with lots of caramalized onions