The term 'Cocktail Slice' refers to a type of dessert that is made with a LEMON-flavored pastry base and topped with a creamy custard. The LEMON flavor comes from the use of LEMON juice and zest, which is often combined with other ingredients such as sugar, butter, and eggs. The custard topping is usually made with cream, sugar, and eggs. The dessert is usually served cold and can be decorated with fresh fruit or other toppings.