Did you know that the Boston Bun has a secret ingredient? Drum roll please… it’s mashed potato!
The Boston Bun dates back to the early 20th century in Australia where mashed and sieved potato was commonly used as an economical substitute for flour.
So does it taste like potato? Nope. Not one bit. Mashed potato actually makes this bun ultra moist, light and fluffy. Combined with plenty of dried fruit and spices, it’s ridiculously delicious.
Traditionally, this sweet treat is also topped with a rich buttercream frosting and lots of desiccated coconut. Try it for yourself and see why this bun has stayed popular for over a century!
How To Make A Classic Boston Bun
The Boston Bun batter starts with creaming together the mashed and sieved potato, butter and sugar. This makes the batter thick, pale and fluffy, which guarantees a moist and delicious bun!
Pour the batter into the prepared tin and bake until golden and a skewer inserted comes out clean.
Allow the bun to cool then slather it with a rich and creamy buttercream icing.
Top with as much coconut as you like!
And there you have it, a classic Boston Bun. Make sure to save yourself a slice (or two) before family or friends get to it!
For the Bun
- 2 cups self-raising flour
- 1 tsp cinnamon
- 1/2 tsp mixed spice
- 1 pinch salt
- 125 g (4.5 oz / 1/2 cup) unsalted butter, softened
- 1 cup caster sugar
- 1 cup mashed potato, at room temperature
- 2 eggs
- 1 tsp vanilla essence
- 1/2 cup milk
- 1/2 cup sultanas
- 1/2 cup currants
For the Icing
- 60 g (2 oz / 1/4 cup) unsalted butter, softened
- 1/2 tsp vanilla essence
- 1 cup icing sugar / confectioners sugar
- 2 tbsp milk, or more as required
- 1/4 cup desiccated coconut
For the Bun
- Preheat the oven to 180 C (355 F). Grease and line a 20 cm (8 inch) round cake tin with baking paper.
- In a medium mixing bowl, sift together flour, cinnamon, mixed spice, and salt. Whisk until combined.
- In a separate large mixing bowl of an electric mixer (or you can use a hand mixer), press the mashed potato through a fine sieve. Add butter and sugar and beat together until fluffy and well combined. Add eggs, one at a time, beating well in between each addition. Add vanilla and beat until well combined.
- Slowly pour a quarter of the milk into the butter mix. Beat until well combined. Follow with one quarter of the flour and spice and beat until combined. Repeat until all the milk and flour is incorporated. Fold in sultanas and currants.
- Pour the mixture into the prepared tin and spread out evenly with the back of a spoon. Bake for 45-50 minutes, or until golden in colour and a skewer inserted comes out mostly clean. Allow to cool in the tin for 10 minutes before transferring to a wire rack to cool completely.
For the Icing
- In the medium bowl of an electric mixer (or using a hand mixer), beat together the butter and vanilla with an electric mixer until pale and creamy. Sift over icing sugar and beat until smooth and well combined. Slowly stream in milk and beat well. If icing is too stiff, slowly add more milk until it reaches a softer consistency.
- Spread icing evenly over the cooled bun and sprinkle generously with desiccated coconut.
- You can keep the Boston Bun un-refrigerated in an airtight container for up to 4 days.
- To freeze the cooked Boston Bun, allow to cool completely (don't use icing) then wrap tightly in clingwrap and place in a large zip-loc or freezer bag. Keep for up to 6 months frozen. To thaw, allow to defrost at room temperature for 6 hours or overnight. Once defrosted, you can ice the bun as normal.
Substitutions & Tips
- Flour: You can replace 2 cups of self-raising flour with 2 cups of plain flour combined with 1 tbsp of baking powder.
- Dried fruit: You can substitute the sultanas and currants for any combination of mixed dried fruit as long as you have 1 cup total.
Nutrition Information:Serving Size: 1/10th of Bun
Amount Per Serving: Calories: 460Total Fat: 17.8gSaturated Fat: 11.4gTrans Fat: 0gUnsaturated Fat: 0gCholesterol: 37mgSodium: 467.2mgCarbohydrates: 69.4gFiber: 5.3gSugar: 43.3gProtein: 6g