To make the tangzhong, place the flour in a saucepan and gradually whisk in the water to avoid lumps. Place the pan over a medium/low heat and whisk constantly until the mixture has thickened to a soft paste/pudding-like consistency.
20 g (3 Tablespoons) white bread flour, 120 g (½ cup) water
Scrape the tangzhong into the bowl of a stand mixer fitted with a dough hook and pour the cold milk on top. This will cool the tangzhong down so that it doesn't kill the yeast.
120 g (½ cup) unsweetened non-dairy milk (I use soy)
Add the sugar, salt, flour and finally the yeast. Mix to form a shaggy dough.
40 g (3 Tablespoons) caster or granulated sugar, ½ teaspoon table salt, 300 g (2 ½ cups) white bread flour, 7 g (2 ¼ teaspoons) instant/fast action yeast
Knead with the mixer on a medium speed until the dough is smooth and stretchy, about 5-10 minutes. It is a very soft, sticky dough; resist the urge to add extra flour unless the dough is wet rather than just sticky.
Add the softened vegan butter. Continue to knead until the butter is fully incorporated and the dough is smooth and elastic. It may seem greasy and messy at first but keep kneading and I promise you the butter will all mix in and the dough will become smooth. Once the butter is fully incorporated the dough should look smooth and silky and it should pass the windowpane test (you should be able to stretch a portion of the dough thin enough to see light through it without it tearing). It should still be soft and sticky however.
35 g (2 ½ Tablespoons) vegan block butter
Lightly oil a large bowl and your hands then shape the dough into a ball. Place the dough in the bowl, cover and set aside to rise in a warm spot until doubled in size, about 1.5-2 hours.
Punch down the risen dough and give it a very brief knead to knock out any air bubbles then divide it into 8 even pieces - use a scale for accuracy. (You can make 6 giant iced buns instead of 8 if you want). Shape each piece into a ball, lightly flouring your hands and the work surface as needed.
Roll one of the balls of dough out on a lightly floured surface into a rough rectangle shape. It doesn't need to be too thin. Pull out the top corners so that the top is slightly wider than the bottom.
Starting at the shorter end, roll it up tightly like a Swiss roll, stretching out the top corners as you go so that it remains the same width the whole way across the roll.
Pinch the ends and seam together to seal them. Roll the finger of dough briefly on the work surface if needed so that it is even across it's length and is about 12-15cm long. Repeat with the rest of the balls of dough.
Line 1-2 baking trays with baking paper and place the dough fingers seam side down in a row, slightly spaced apart.
Loosely cover and set aside to rise until puffy, about 45-60 minutes. If you press one gently the dough should spring back slowly most of the way but leave a small indentation. If it springs back quickly and fills in all the way then they need a little bit longer. While they are rising preheat the oven to 200°C/180°C fan/400°F/gas mark 6.
When the buns are ready to bake, gently brush them with a little milk, then bake for 12-15 minutes until light golden and the internal temperature reaches 90°C/194°F on a probe thermometer.
non dairy milk for brushing
Remove from the oven and transfer to a wire rack to cool. Make sure that they have cooled completely before making the icing.
If you are making the icing with water, sift the icing sugar into a bowl, add the vanilla if using, and gradually stir in enough cold water to form a thick but spoonable consistency, about 1-2 Tablespoons. You can add a drop of food colouring if you like.
200 g (1 + ¾ cups) icing (powdered) sugar, ½ teaspoon vanilla extract
If you are making the icing with blueberries, place the blueberries in a small bowl and mash with a fork. Scrape the mashed blueberries through a fine mesh sieve and discard the skin. Gradually stir the blueberry juice and vanilla into the icing sugar to form a thick but spoonable consistency, you may not need all of the blueberry juice.
60 g (⅓ cup) fresh blueberries OR use 1-2 Tablespoons water*
Spoon some of the icing on top of each bun and spread it across the top with the back of a spoon. Leave to set for 20 minutes or so then serve.