Grease a 9 or 10 inch pie pan with butter.
Add the flour, yeast, and salt to the bowl of a stand mixer preferably with a dough hook attachment and add the butter.
Squeeze the butter with your fingers until it’s almost like sand.
Add the egg and milk and mix for 4-5 minutes to form a dough.
Place the dough in another bowl that’s been lightly greased with some olive oil.
Cover with a towel and leave in a warm place until doubled in size. About 1 hour depending on humidity.
Punch down the dough on a table dusted with flour and roll the dough into a rectangle about 12 x 10 inches.
To make the filing, cream the 2 oz of butter with the cinnamon and dark brown sugar. Spread the filling evenly all over the dough.
Starting at the top of the longest side of the dough, start to roll it tightly towards you to create a cylinder shape.
Slice the roll with a sharp knife into 12 pieces placing them in the pie pan facing the insides upwards.
Cover and leave for about 40 minutes.
Bake in a 375 degree preheated oven for about 20 minutes.
Let cool while you make the frosting.
In a bowl combine the powdered sugar with some milk and whisk until there are no more lumps visible.
Pour the icing over the semi-warm cinnamon roll and eat straight away.