Prepare the Dough: In a mixing bowl, combine the cake flour, castor sugar, softened butter, and powdered milk (if using). Mix well and knead until the dough is smooth and pliable.

Shape the Donuts: Roll out the dough onto a floured surface to about 1/2 inch thick. Use a donut cutter to cut out donut shapes. Don’t worry if you experience a few first-time fails; it’s all part of the fun!

Fry and Brown: Carefully heat vegetable oil in a deep pan over medium heat. Once the oil is hot (about 350°F), drop in the donuts, frying until they are golden brown, usually about 2-3 minutes per side. Use a slotted spoon to remove them and drain on paper towels.

Coat and Fill: While hot, roll the donuts in the extra castor sugar to coat. Let them cool slightly before injecting them with the fresh cream. You can use a piping bag equipped with a filling tip for this task.