What is "filled cookie"?

Filled cookies are a type of cookie made with two layers of dough or batter, with a filling in between. The dough or batter is usually made with a combination of ingredients such as flour, sugar, butter, eggs, and flavorings. The filling can be anything from a jam or jelly to a cream or custard. Filled cookies are often decorated with a variety of toppings such as chocolate chips, nuts, dried fruits, and sprinkles. They are a popular choice for parties and gatherings, as they are easy to make and can be filled with a variety of flavors.