In a mixing bowl, combine warm milk, active yeast, sugar, flour, and oil. Mix until a sticky dough forms, then knead on a floured surface for about 5-10 minutes until the dough is smooth and elastic.

Roll the dough gently to remove any air bubbles. Fold it over and press down several times to develop elasticity.

Divide the dough into 10 equal portions and roll each piece into a smooth ball. Flatten each ball into a disc approximately 3 inches in diameter.

Whisk together eggs, milk, melted butter, and flour in a separate bowl until smooth for the custard filling.

Take one dough disc and place a spoonful of custard filling in the center. Fold the edges over the filling and pinch to seal.

Cover the buns with a clean cloth and let them rest for 30 minutes in a warm place.

Bring your steamer to a gentle boil, then carefully place the buns inside. Steam over medium heat for about 10 minutes.