The crossword solution for the term 'Sponge Cake Ingredients' is 'EGGS', which is a four-letter word. Eggs are a common ingredient in many types of cakes, including sponge cakes. They provide structure and stability to the cake, as well as flavor and moisture. Eggs also help to bind the other ingredients together. In sponge cakes, eggs are usually beaten until they are light and fluffy, which helps to create a light and airy texture.