The term 'simmer slowly' is often used in cooking, and can be defined as a method of cooking food in liquid at a low temperature, just below the boiling point. The crossword solution for this term is 'STEW', which is a type of dish that is cooked by simmering slowly. Stews are usually made with vegetables, meat, and a flavorful liquid, and are cooked for a long period of time to allow the flavors to blend together.