I love my slow cooker. perhaps you are not cooking it for a long enough period. Just put the stewing beef, onions , lentils , tin of chopped tomatoes, sliced carrots , potatoes if you like , a dash of Worcestershire sauce , maybe a squirt of tomato ketchup a little sat and pepper. Cover with water , make gravy with oxo or granules and add to casserole. A powdered stew mix can be added if you like. Stir , put lid on ,switch on at about 9am on high and walk away. No pre browning of meat necessary. Meal will be ready any time after about 5pm. It will cook for hours without spoiling. Enjoy, it's really easy!!