Fixing a thin soup is as simple as carefully reducing the soup a little. u003cbr/u003eu003cbr/u003eDo not be tempted to add more lentils halfway through cooking as you will end up with some raw and some cooked. u003cbr/u003eu003cbr/u003eIf the soup is too thick simply add a touch of stock, cream or water and gently heat it up while stirring.