Sourdough Macadamia Nut Sweet Rolls

We recently spent a week in Hawaii, and while I couldn't bring back any fresh fruit, I was able to bring back some good macadamia nuts (Sea Salt Roasted).  Wanted to use some of them in a bake and came up with the following idea.  I used the Sourdough Cinnamon Roll recipe from Breadtopia's Sourdough Cookbook for Beginners (Pg. 102) as the basis for the recipe and then developed my own filling using the macadamia nuts.  Gave a few to friends, and the early reviews are great!  

Sweet Stiff Starter
90g   AP Flour
30g   Sourdough Starter at 100% hydration
40g   Water
30g   Granulated Sugar

Final Dough
450g   AP Flour
50g    Spelt Flour, fresh milled
130g  Scalded Milk
86g    Unsalted Butter, cubed
120g  Granulated Sugar
10g    Salt
6g      Vanilla Extract
150g  Eggs (3 large eggs)

Filling
150g  Granulated Sugar
75g    Chopped Macadamia Nuts
2 tsp  Orange zest
1 tsp  Orange juice (fresh squeezed)
3/4 tsp Cardamom
1/2 tsp Myer's Dark Rum
1/2 tsp Vanilla Extract

Icing
2 cups  Powdered Sugar
1 tsp     Myer's Dark Rum
1/2 tsp  Vanilla Extract
2-3 TBSP  Milk

Morning Before
1)  Combine ingredients for Sweet Stiff Starter and kneading a few times to completely mix/hydrate flours
2)  Ferment 6-12 hours at 76 deg F until dough has doubled in size

Night Before
1)  Mix all Final Dough ingredients including Sweet Stiff Starter with paddle attachment until dough just comes together.
2)  Knead dough using dough hook attachment for 10-15 minutes on medium speed (I was unable to fully develop dough and keep it from sticking to bowl.
3)   Scrape dough into greased bowl and ferment at 76 deg until at least a 75% volume increase. Will take 6-12 hours. (I was able to get 100% in 10.5 hours) 
3)  Combine Filling ingredients in a bowl and mix thoroughly to wet the sugar (should have wet sand consistency).  Cover and refrigerate to allow flavors to come together.

Day Of
1)  Roll dough on a lightly floured surface into a 24" x 12" rectangle keeping corners relatively square and to a uniform thickness.  If dough sticks to counter, lightly flour the top side and flip the dough.  Lightly flour the new top side and continue rolling.
2)  Place filling on dough and evenly distribute it.  Leave about 1/2" of open dough along the top edge to seal the roll.
3)  Roll dough away from you keeping the roll as tight as possible and uniform in shape/thickness.
4)  Grease a 13" x 9" x 2" baking dish.
5)  Cut the roll into 2" long sections and place cut-side up in the dish.  Evenly space the 12 rolls in the dish.
6)  Cover the dish and let rise 3-5 hours at 75+ deg F.  Dough will expand significantly and the rolls will touch each other.  (I stopped final proof at 3.75 hours (76-77 deg F)).
7)  Pre-heat oven to 350 deg F and then another 15 minutes
8)  Bake at 350 deg F for 25-30 minutes until edges are light golden brown and filling is bubbling (I went a couple minutes too long).
9)  Combine ingredients for icing and mix until no sugar lumps with a whisk.  Add milk/sugar as needed to get desired consistency.
10)  Remove rolls from oven and let cool in pan for 5-10 minutes.  Drizzle icing over rolls and let the icing firm up.

Rolls after Final Proof