Tip the flour, yeast and cardamom into the bowl of a stand mixer. Warm the milk, sugar and 1 tsp sea salt in a pan over a low heat until the sugar has melted and the milk is steaming. Remove from the heat and stir in the butter to melt. Cool to room temperature. Once cool, add this to the dry ingredients in the stand mixer bowl. Mix with dough hook for 7-9 mins until smooth and elastic, or knead by hand for 10-12 mins. Cover and leave to prove for 1 hr until doubled in size.

Heat the oven to 180C/160C fan/gas 4. Butter a 25cm round cake tin and line the base with parchment. Make the cinnamon butter by beating the butter, sugar, cinnamon and clementine zest together. Roll the dough out on a lightly floured surface into a roughly 40 x 25cm rectangle. Thinly spread over the butter, then roll up into a spiral from a long edge. Slice into 10 pieces, about 4cm thick.

Arrange the swirls in the tin, cut-side up, leaving 1-2cm between them. Cover and prove in a warm place for 35-40 mins, then bake for 30-40 mins until risen and golden. Cool on a wire rack.

Combine the icing sugar, cinnamon and clementine juice to make a thin glaze. Drizzle this over the cooled buns, then serve.