For the dough: Place the flour, sugar, salt and yeast into a large bowl and mix together with a silicone spatula until combined. Then make a well in the centre and pour in the milk and aquafaba. Mix with the spatula until a rough dough forms. Then, flour your work surface generously and removing the dough from the bowl, knead for 5 minutes until the dough has a smooth skin.
Add the butter to the dough, one tablespoon at a time, kneading as you go so the butter is completely combined. You will need to re-flour your work surface a few times throughout, as the dough will be very sticky. (If you have a dough scraper, this will also help to manoeuvre the dough.) This process should take around 10 minutes.
Once all the butter has been combined, continue kneading the dough for a further 10 minutes until the dough is smooth and pliable and no longer sticky. Lightly oil a large bowl, place the dough inside and cover with clingfilm. Leave this to prove for at least an hour until the dough has doubled in size.
For the topping: When your dough has around 30 minutes left of proving time, begin making the topping. Roughly chop the walnuts and lay them in the base of a greased baking tin, around 26x30cm. Then peel, core and chop the pears into medium chunks and scatter them in the baking tin with the walnuts. Then in a medium saucepan combine the butter, sugar, milk, golden syrup and salt and place over a medium-high heat. Cook until the butter has melted, then turn up the heat and boil for 3 minutes stirring every now and then. Take off the heat, pour over the walnuts/pear and set aside.
For the filling: In a small bowl, combine the butter, sugar and cinnamon until smooth and a thick paste. Then set aside.
To assemble: Lightly flour your work surface, tip out the risen dough and knock back slightly, by folding in on it self a few times. Then using a rolling pin, roll out to a large rectangle approx. 30x45cm. Then using a palette knife or spoon, spread the filling evenly across the dough. Then roll up from the long side, so you get a spiral of dough with the filling inside. Slice off the edges if they're not exactly straight, then cut the roll into 12 pieces. Arrange these over the walnut/pear caramel topping, and leave to rise in a warm place for around 45 minutes. Your dough will have puffed up and spread once they are ready.
Preheat the oven to 180C/160C Fan/Gas Mark 4 while the the buns are proving. Then bake for 25 minutes until golden and bubbling at the sides. Leave the buns to cool in the tin for 5 minutes, before inverting the tin onto a serving platter. Enjoy warm.