If you have ever visited a traditional Chinese dim sum restaurant, you may have seen soft white buns that look simple from the outside but hide a rich, creamy filling inside. These delicious buns are called Steamed Custard Bun, also known as Nai Wong Bao in Cantonese cuisine.

These fluffy steamed buns are filled with a sweet custard made from egg yolks, milk, sugar, and butter. The combination of the light, pillowy dough and the creamy filling makes them one of the most popular dim sum desserts.

In this blog, you will learn everything about making authentic Chinese Steamed Custard Buns at home.

What Is Steamed Custard Bun?

Steamed Custard Bun is a classic dessert bun commonly served in Dim Sum restaurants across Southern China, especially in the Cantonese region.

These buns feature:

Soft and fluffy white steamed dough
Sweet and creamy egg custard filling
Mild vanilla and buttery aroma
Smooth melt-in-the-mouth texture

They are usually served warm in bamboo steamers during dim sum brunch.

Ingredients

For the Custard Filling

3 egg yolks
½ cup sugar
2 tablespoons custard powder
1 tablespoon cornstarch
1 cup milk
2 tablespoons butter
1 teaspoon vanilla extract
Pinch of salt

For the Bun Dough

2 cups all-purpose flour
2 tablespoons sugar
1 teaspoon instant yeast
¾ cup warm milk
1 tablespoon vegetable oil
½ teaspoon baking powder

Step 1: Prepare the Custard Filling

  1. In a bowl, whisk egg yolks and sugar until smooth.
  2. Add custard powder and cornstarch and mix well.
  3. Slowly pour in the milk while stirring to avoid lumps.
  4. Transfer the mixture to a saucepan and cook over low heat.
  5. Stir continuously until the mixture thickens into custard.
  6. Add butter, vanilla extract, and a pinch of salt.
  7. Cook for another 1–2 minutes until smooth and creamy.

Remove from heat and let it cool completely.

Once cooled, refrigerate for 30 minutes so the filling becomes firm enough to wrap.

Step 2: Prepare the Bun Dough

  1. In a mixing bowl, combine flour, sugar, and yeast.
  2. Add warm milk and oil.
  3. Knead the dough for about 10 minutes until smooth and elastic.
  4. Cover the dough and let it rise for 1 hour or until doubled in size.

After rising, knead again and mix in the baking powder.

Step 3: Shape the Custard Buns

  1. Divide the dough into 10–12 equal portions.
  2. Flatten each portion into a small circle.
  3. Place 1 tablespoon custard filling in the center.
  4. Gather the edges and seal tightly to form a bun.
  5. Place each bun on small parchment squares.

Let the buns rest for 15 minutes before steaming.

Step 4: Steam the Buns

  1. Heat water in a steamer.
  2. Arrange the buns in a bamboo steamer with space between them.
  3. Steam over medium heat for 10–12 minutes.

Once done, turn off the heat and let them rest for 2 minutes before opening the lid.

Tips for Perfect Steamed Custard Buns

✔ Use warm milk, not hot, to activate the yeast properly.
✔ Chill the custard filling before stuffing the buns.
✔ Do not overcrowd the steamer.
✔ Let the buns rest after steaming to prevent shrinking.

Variations

Lava Custard Bun

Some modern dim sum restaurants serve custard buns with molten filling.

Salted Egg Custard Bun

Made with salted egg yolks for a richer flavor.

Chocolate Custard Bun

A fusion version popular in modern bakeries.

Serving Suggestions

Steamed Custard Bun is best served:

Hot and fresh from the steamer
With Chinese tea
As part of a Dim Sum meal

They are perfect for breakfast, brunch, or dessert.

Storage Tips

Refrigerate leftover buns for up to 3 days.
Reheat by steaming for 5 minutes.
You can freeze uncooked buns for 1 month.

Final Thoughts

Soft, fluffy, and filled with sweet creamy custard, Steamed Custard Bun is one of the most beloved treats in Chinese cuisine. Whether you are a fan of Dim Sum or simply love steamed buns, this recipe is a must-try.

With simple ingredients and easy steps, you can recreate this restaurant-style delicacy right in your kitchen.