For the filling
Rub together butter, sugar and cinnamon; set aside.
For the dough
Place honey and milk in a jug, stir to dissolve; add yeast, stir briefly, cover with clingfilm and set aside until foamy and doubled in size.
Sift flour and salt into a bowl, stir through sugar and rub in the butter. Make a well in the centre. In a bowl, whisk together eggs and apple juice, stir in yeast mixture then add all the liquid to dry ingredients.
Stir to combine, then turn dough out onto a floured surface and knead well for 10 minutes. Place in an oiled bowl; cover with clingfilm. Allow to stand for 1 hour.
Knock back dough and knead for 2 minutes. On a floured surface, roll out into a large (50 x 35cm) rectangle.
Scatter over the filling mixture and the walnuts; sprinkle over the raspberries. Roll up from the longest side, as you would a Swiss roll.
Cut the sausage into 15×2cm pieces/rounds. Place the rounds in the prepared tin to fit snugly and allow to stand for 30 minutes or until doubled in size.
Preheat the oven to 180°C.
Grease a 30cm x 35cm rectangular deep baking tin.
Brush dough with egg and bake for 30 minutes. Remove from oven and allow to cool, then drizzle with topping.
For the topping
Combine icing sugar and juice in a small bowl and drizzle over cinnamon buns.
Sprinkle with extra raspberries and dust with icing sugar.