Taro “Rotiboy” Buns

This soft milk bun is stuffed with sweet taro paste and topped with a crunchy sugar cake coating!

Have you ever heard of a Mexican concha bread or Rotiboy coffee bun? If not, let me quickly introduce you to these because these breads are delicious sweet breads that go so well with coffee. A mexican concha bread is a soft roll with a seashell like appearance. The plain roll is topped with a crunchy topping that consists of sugar, butter, and flour. The crunchy topping technique is used in all cultures, such as the Cantonese bolo pineapple bun, and it’s main purpose is to add flavor and texture to a plain bread. There is a chain bakery in Malaysia, called Rotiboy, that created their own version of the concha bread, but without the seashell pattern. Their buns are coffee-flavored, but I’m using their rotiboy bun as inspiration and creating one that is stuffed with taro instead.

I wanted to use taro because I recently had a large taro harvest from my garden! You certainly don’t need homegrown taro for this recipe; just buy it from an Asian or African grocery store. This bread is absolutely divine and gourmet. It requires multiple steps and a few hours, but it is so worth it. I feel like I got these from an upscale bakery! The bread itself is very soft, the taro is fragrant, and the crunchy topping is sweet and it boasts a vibrant purple color. I enjoy these buns for breakfast and snack time.

To make this recipe, you will need the following “special” ingredients:

How do I prepare taro?

To prepare taro root, put on a pair of disposable gloves or kitchen gloves. Taro contains oxalic acid which can irritate skin. Oxalic acid is destroyed during the cooking process. If you don’t have gloves, coat your hands with oil. Rinse the taro root and peel the outer dark skin with a heavy duty peeler. Be careful! Taro root is quite tough. Once peeled, cut the root into small cubes and boil or steam until soft, about 10-15 minutes.

What is tangzhong/The secret to super soft bread:

Tangzhong is a Taiwanese bread ingredient that results in soft, fluffy bread and long-lasting moisture. Tangzhong is a starchy gel made of water and flour. It is a starchy gel that provides a soft texture to breads. The tangzhong roux requires 2 simple ingredients, water and flour, but works very effectively in bread dough. It prevents recrystallization which is the cause of stale bread.

Taro “Rotiboy” Buns

yield: 6 large buns

total cook time: 3 hrs


For dough:

  • 27 g. or 3 tbsp. bread flour + 30 g. or 1/2 c. water for tangzhong roux (Read above to learn about tangzhong)
  • 95 g. or 1/4 c. + 2 1/2 tbsp. lukewarm water
  • 4 g. or 1 tsp. active yeast
  • 6 g. or 1 tsp. salt
  • 20 g. or 1 1/2 tbsp. granulated sugar
  • 410 g. or 3 c. bread flour
  • 8 g. or 2 tbsp. milk powder (NOTE: if you do not have milk powder, you can replace the lukewarm water with lukewarm milk and omit the milk powder. You may have to add some additional bread flour)
  • 50 g. or 1 large egg
  • 20 g. or 1 1/2 tbsp. softened unsalted butter

For taro filling:

  • 275 g. or 2 c. steamed taro (Read above on how to prepare taro root)
  • 10 g. or 2 tsp. softened unsalted butter
  • 30 g. or 2 tbsp. + 1 tsp. sugar (use more if desired)
  • 15 g. or 1 tbsp. milk

For topping:

  • 60 g. or 1/4 c. softened unsalted butter
  • 50 g. or 1/4 c. sugar
  • 50 g. or 1 large egg
  • 50 g. all-purpose flour
  • 10 g. or 2 tsp. Taro powder or purple sweet potato powder (Use purple sweet potato powder for a deeper purple color)


  1. Prepare the tangzhong first. In a small pot, whisk together the 3 tbsp. bread flour and 1/2 c. water over medium-low heat. Whisk frequently until the roux thickens and turns into a sticky paste. This takes about 4 minutes. Remove from heat and set aside to cool for 20 minutes.
  2. In a stand mixer, add water, yeast, salt, sugar, milk powder, bread flour, and tangzhong. Knead on medium speed for 2 minutes. Add in the egg and softened butter and knead for an additional 13 minutes. Place the dough in a large bowl and cover it with a lid or towel. Rest for 1 hour in a warm place. The dough should double in size.
  3. While the dough is rising, prepare the taro filling. Mash the steamed taro in a bowl with a fork and add the remaining filling ingredients. Taste and add more sugar if desired. I chose not to make the filling very sweet since there will be a sugar crust on the bread.
  4. Using oiled hands or gloves, roll the taro paste into 6 balls. Each ball should be 1 1/2 tablespoons full. Place on a piece of parchment paper and freeze for at least 30 minutes.
  5. To make the sugar crust, whisk together butter and sugar in a small bowl. Whisk the egg in. Add the flour and taro or purple sweet potato powder and whisk until smooth. Set aside. Add the sugar mixture to a piping bag or Ziploc bag.
  6. Once the dough has doubled in size, punch the dough and separate it into 6 equal pieces. Roll out the dough a bit and add 1 frozen taro filling ball (watch video for clarification). Seal the edges of the dough and place it on a baking sheet with parchment paper, seamed edges downwards. Repeat for the remaining dough.
  7. Cover the prepared buns and allow them to rise in a warm place for 30-45 min.
  8. Preheat oven to 365 F.
  9. Once the buns have rested for 30-45 min, pipe on the sugar filling in a circular motion. Pipe the filling until halfway down the bun (watch video for clarification).
  10. Bake the buns for 25 minutes at 365 F.
  11. Remove the baked buns from the oven and cool for 10 minutes. Enjoy!

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