Nikuman (Steamed Beef Buns)

Mix milk and sugar for dough together in a bowl. Pour bun flour into another bowl and add gradually the milk mixture, stirring with a spatula.

Form the dough into a ball and knead with your hands for about 20 minutes. Add olive oil and knead for 10 minutes more.

Transfer dough to a dry bowl, cover with a towel, and let rest for 30 minutes.

Combine beef, mushrooms, green onions, cornstarch, sugar, soy sauce, oyster sauce, sesame oil, salt, five-spice powder, and pepper in a bowl with your hands until thoroughly mixed. Form the filling into 12 equally sized meatballs.

Roll dough on a lightly floured surface and cut into 12 equal pieces. Roll each piece out with a rolling pin to a circle, no more than 5 inches in diameter.

Cover each meatball with a dough circle, pinching the edges to close.

Place a steamer insert into a saucepan and fill with water to just below the bottom of the steamer. Bring water to a boil. Add beef buns, working in batches as needed, cover, and steam until meat is no longer pink, about 45 minutes.