In a large mixing bowl, combine 4 cups of all-purpose flour, ½ cup of granulated sugar, 2 teaspoons of instant yeast, and 1 teaspoon of salt.

In a separate bowl, whisk together 2 large eggs, 1 cup of warm milk, ½ cup of melted butter, and 2 teaspoons of vanilla extract.

Gradually stir the wet mixture into the dry ingredients until a shaggy dough forms.

Transfer the dough onto a lightly floured surface and knead for about 10 minutes until it's smooth and elastic.

Grease a large bowl and place the kneaded dough inside, turning to coat. Let rise for about 1 hour.

In a medium saucepan over medium heat, mix ½ cup of custard powder, ½ cup of sugar, and 2 cups of milk. Stir constantly until thickened, about 5-7 minutes.

Punch the dough down gently, roll it out into a rectangle, and spread the cooled custard filling evenly over it.

Roll the dough into a log and cut it into pieces, about 2 inches each.

Arrange the pieces in a greased baking dish and allow them to rise for 30-45 minutes.

Preheat the oven to 350°F (175°C) and bake for 25-30 minutes.

Cool in the pan for about 10 minutes and transfer to a wire rack to cool slightly before dusting with powdered sugar.