If you have time, prepare the dough the day before you want to bake – this will help develop the flavour. Warm the milk in a pan over a medium heat until just steaming (don’t let it boil), about 5 mins. Remove from the heat and add the treacle and butter, swirling the pan for 1-2 mins until the butter has melted and the milk has cooled slightly (it should be just warm).

Tip the flour and spices into a large bowl, or the bowl of a stand mixer. Add the yeast and 2 tbsp sugar to one side of the bowl, and 1/2 tsp salt to the other. Whisk together, then pour in the warm milk mixture. Mix using a wooden spoon or dough hook attachment until you have a soft dough (it should be a little sticky). Tip onto a lightly floured surface and knead by hand for 8-10 mins, or using the mixer for about 5 mins. Add another 1 tbsp flour if the dough is very sticky. It should feel stretchy and soft – you should be able to pull it without it breaking straightaway, which indicates the gluten has been developed. Lightly oil a bowl, tip in the dough, cover and leave to prove at room temperature for 2-3 hrs, or until doubled in size. Chill overnight if you can. (If the dough is being chilled, take it out of the fridge 30 mins before using.

For the spiced butter, combine the butter, sugar, vanilla, spices and a pinch of salt until smooth, then stir in the stem ginger. Tip the dough out onto a lightly floured surface, shape into a rough rectangle, then roll out to about 50 x 40cm. Spread the spiced butter over in an even layer all the way to the edges.

Working from one of the longer sides, roll the dough up as tightly as you can into a log. Cut in half, then cut each half into three pieces, then halve each piece so you have 12 pieces in total. Line a large, round baking dish or cake tin (about 33cm) with baking parchment. Arrange the buns in the dish or tin cut-side up, leaving some space between each to expand. Cover loosely and leave for 30 mins-2 hrs (depending on how warm your kitchen is) until the buns have puffed up and are touching. Heat the oven to 200C/180C fan/gas 6.

Bake the buns for 25 mins until golden. If they still look a little doughy at the centre but the edges are dark, cover with foil and continue to bake until they are cooked through. Leave to cool slightly in the tin until just warm. Once cool, the buns will keep frozen for three months. Defrost overnight and warm in low oven before icing. Meanwhile, make the icing.

Melt the butter in a saucepan over a medium heat, swirling the pan until the butter turns nut brown – watch closely to ensure it doesn’t burn. You should see the milk solids start to turn golden after 5-8 mins, and it will have a nutty aroma. Pour into a heatproof bowl and chill for 30 mins until softly set, or freeze for 15 mins, stirring every 5 mins. It should be a spreadable consistency.

Beat the chilled brown butter, soft cheese, icing sugar and spices together until smooth. Spread the icing over the buns while they are still slightly warm, so the icing drips into the swirls without melting completely. Leave to set for 30 mins before serving. Will keep for up to three days in an airtight container.