Line a 34cm x 23cm rectangle tin with baking paper and spray with oil.
Mix the butter, brown sugar and cinnamon together to make the filling. Set aside.
Lightly flour your bench and roll out your brioche dough to 250mm x 500mm (check with a tape measure).
Spread over your filling mixture, and use a palette knife to get it right to the edges.
Roll it up into a tight log, starting from the edge closest to you.
Slice into 12 even pieces and place them into your tin, side by side, cut side up.
Cover the tin with cling film and leave it in a warm place to prove. This will take no less than one hour.
Heat your oven to 165°C fan bake.
Take the cling film off the tin and bake for 12–15 minutes, until golden.
Leave the buns to cool for 15 minutes, and in the meantime, make your cream cheese icing.
Pipe the icing onto each one and spread it with a palette knife. Finish with a dusting of icing sugar and serve warm.
These are best eaten the day they are made, but I doubt you would have leftovers anyway!
