The night prior to baking (allow from 7-12 hours), prep dough. Place the flour into a large mixing bowl and cut in the butter(I use my fingertips) until it resembles chunky sand. Stir in sourdough starter, maple syrup, milk and mix until a soft dough forms. Cover and place in a warm spot for 7-12 hours (I leave it on my benchtop).
The next morning, or 7 or so hours later, preheat oven to 350˚F / 180˚C.
Combine salt, baking powder and baking powder. Sprinkle this mixture over the fermented dough and knead the mixture in the bowl until it comes together as a soft dough. This will only take a few turns – don’t overmix!
In a small bowl, make the filling by combining the melted butter with the cinnamon and brown sugar to form a paste.
Flour your benchtop and rolling pin well. Roll out the dough into a ¼ to ½ inch thick rectangle (mine measured about 18 inch x 14 inch). Spread the filling evenly across the entire dough surface, and sprinkle over the walnut pieces. Then, starting with the long side of the rectangle, roll it up tightly. Cut into 1 inch thick slices.
Spray a large baking dish or tray with oil (I use my 3.2-Qt. Lodge cast iron combo cooker which has a 10.25-inch shallow skillet as a lid). Place the scrolls in the pan and bake for 25-30 mins or until golden.
Meanwhile, to make the honey caramel glaze, melt the butter in a small pan. Stir in the brown sugar, honey, salt and cream. Bring it the boil, and then reduce heat to medium. Simmer for 5 minutes, until glossy and golden brown.
While the buns are warm, spoon caramel over the top and sprinkle with extra walnuts. Eat warm.