Custard-filled donuts are sweet pastries made from a soft, fried dough that is filled with a creamy custard filling. The dough is typically leavened with yeast, giving it a light and airy texture. After frying, the donuts are often coated in powdered sugar or glazed for added sweetness. The custard filling is usually made from milk, sugar, eggs, and vanilla, creating a rich and smooth flavor. These donuts are popular in many bakeries and are enjoyed as a delicious treat for breakfast or dessert. They can be found in various sizes and are sometimes topped with chocolate or fruit glazes.