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Bolu Gulung (Rainbow Swiss Roll)


  • Stove top steamer
  • Rectangular baking pan (as shown)
  • Parchment paper
  • Cooking oil
  • Ziplock bags or piping bags



  • 75 g sugar
  • 3 yolks
  • 2 egg whites
  • 1/2 tsp emulsifier such as Sp, Ovalet, VX - can be purchased at specialty store for bakers, online, and/or Asian stores
  • 1 tsp vanilla essence
  • 40 g flour
  • 5 g cornstarch
  • 5 g milk powder I got mine full cream at Bulk Barn. You can use skim milk powder from Walmart or even coffee creamer
  • a pinch of salt
  • 50 ml oil
  • food color I use 5 differ colors


  • 60 ml pasteurized egg whites
  • 226 g icing sugar
  • 1 lb unsalted butter
  • a pinch of salt
  • 1 tbsp vanilla essence subs with other flavor according to your liking!



  • Preheat steamer for about 15 minutes on high heat then turn heat to super low
  • In a bowl, mix dry ingredients (flour, salt, milk powder, cornstarch)
  • In a separate bowl, beat yolks, egg whites, sugar, emulsifier, vanilla essence until fluffy and thickened, over high speed
  • Lower speed to medium and beat in flour mixture
  • Beat in oil until combined well
  • Divide batter into 5 bowls and add food coloring into each bowl
  • Pour each colored batter into ziplock bags and snip the corner
  • Pipe batter alternating one to another on parchment lined baking pan which already greased with oil
  • Turn up oven heat to high again and steam cake for 10 minutes
  • On table, place a clean parchment paper and turn over steamed cake on paper
  • Peel off paper from cake that was used for steaming
  • Roll cake slowly and let it stand for 10 minutes


  • Mix egg whites with icing sugar then beat to combine
  • Beat in butter a little at a time until fluffy and creamy
  • Beat in a pinch of salt followed with vanilla essence

Swiss Roll

  • Unroll cake and spread buttercream
  • Reroll cake and slice to serve