Dessert

Dim Sum Steamed Custard Buns (Nai Wong Bao) Recipe

ByRafael Mansero April 11, 2026April 11, 2026

Introduction

Dim Sum Steamed Custard Buns, or nai wong bao, are soft, fluffy buns filled with a creamy, sweet custard. These delightful treats are perfect for a comforting snack or a special dessert. Making them at home is easier than you might think!

A black round plate with three smooth, white steamed buns on white parchment, with one bun cut in half and placed on top, showing a soft, fluffy white outer layer and a pale yellow creamy filling inside, all set on a white marbled surface. photo taken with an iphone --ar 4:5 --v 7

Ingredients

2 large eggs
⅓ cup + 1 tbsp whole milk
½ cup sugar
¼ cup butter
¼ tsp salt
¼ cup cake flour
¼ cup powdered milk
⅔ cup whole milk
1 tsp active dry yeast
2 cups all-purpose flour
1 tbsp vegetable oil
2 tbsp sugar

Instructions

Step 1: Make the custard filling by whisking eggs and ⅓ cup + 1 tbsp milk in a small pot. Add ½ cup sugar and ¼ tsp salt, mixing well.
Step 2: Sift cake flour and powdered milk into the egg mixture, stirring until smooth. Add butter and heat over low heat, stirring constantly until thickened into custard. Remove from heat and let cool. Cover and refrigerate.
Step 3: Prepare the bun dough. In a large bowl, combine ⅔ cup milk, 1 tsp yeast, 2 tbsp sugar, 2 cups all-purpose flour, and 1 tbsp vegetable oil. Mix using a stand mixer with a dough hook on low speed for 5 minutes, then medium speed for 5 more minutes, until smooth and white. Alternatively, knead by hand for 8-10 minutes until smooth and elastic.
Step 4: Divide the dough into 10 equal portions (about 50 g each). Cover to prevent drying.
Step 5: Roll each portion into a log and fold both ends toward the middle, pressing down. Repeat folding two more times to remove air bubbles.
Step 6: Shape each dough ball by folding edges toward the middle and pressing gently while rotating, creating a smooth surface with no cracks. The bottom will have a small “belly button” indentation. Flatten this side, then roll into a disc that’s thicker in the center and thinner at the edges.
Step 7: Divide the custard filling into 10-12 portions. Place one portion in the center of each dough disc, then pleat and seal the top to enclose the filling. Place buns pleated side down on parchment or a lined steamer tray.
Step 8: Let the buns rest at room temperature for about 30 minutes until they rise to 1.5-2 times their original size.
Step 9: Steam the buns for 10-12 minutes. After steaming, turn off the heat and let them rest for 5-10 minutes before carefully opening the lid to avoid water dripping onto the buns.
Step 10: Serve warm and enjoy the soft buns filled with luscious custard.

Tips & Variations

For extra fluffiness, be sure to knead the dough thoroughly until smooth and elastic.
If you don’t have cake flour, you can substitute with all-purpose flour mixed with a bit of cornstarch.
Use parchment paper squares under each bun to prevent sticking during steaming.
Feel free to flavor the custard with a little vanilla extract or pandan for a fragrant twist.

Storage

Store leftover steamed custard buns in an airtight container in the refrigerator for up to 2 days. To reheat, microwave each bun for about 30 seconds until warm and soft. Avoid freezing as it may affect the texture.

How to Serve

The image shows two soft, round buns placed on a black plate lined with white paper. One bun is whole while the other is cut in half, revealing a creamy yellow filling inside. The buns have a pale, slightly powdery outer layer with a smooth, light texture. In the background, a white bowl and some whole buns are slightly out of focus, all set on a white marbled surface. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I make the custard filling ahead of time?

Yes, you can prepare the custard filling a day in advance and refrigerate it. Make sure to cover it tightly to prevent a skin from forming.

How can I tell when the buns are fully steamed?

The buns should rise noticeably and feel soft and fluffy. Steaming for 10-12 minutes is usually sufficient, but avoid over-steaming as it can make the buns soggy.