A custard filled donut is a type of pastry that features a soft, fried dough shell filled with a creamy custard filling. The dough is typically made from flour, sugar, eggs, and yeast, which gives it a light and airy texture. After frying, the donut is often dusted with 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 sweet treat or dessert. They can be found in various sizes and are often served fresh for the best taste.