What is "filled donut"?

A filled donut, also known as a jelly donut, is a type of donut that is filled with a sweet filling such as jam, custard, or cream. The pastry is made from a sweet, yeast dough that is rolled out and shaped into a ball before being deep-fried until it is golden brown and crispy on the outside and soft and fluffy on the inside. Once the donut is cooked, a small hole is made in the side of the pastry, and the filling is injected into the center using a pastry bag or similar tool. The hole is then covered with a glaze or other topping, giving the donut a sweet and flavorful exterior. Filled donuts are a popular pastry in many countries around the world and are often enjoyed as a sweet treat for breakfast or as a snack throughout the day.