What is "Boston cream donut"?

A Boston cream donut is a type of filled donut that is typically made from a sweet, yeast dough that is deep-fried until it is golden brown and crispy on the outside and soft and fluffy on the inside. The pastry is then filled with a vanilla custard or pastry cream, which gives it its characteristic creamy texture and flavor. The donut is often topped with a chocolate glaze or frosting, which adds a sweet and decadent touch to the pastry. Boston cream 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.