Cinnamon buns by Cheryl Lam

Cinnamon buns by Cheryl Lam
https://www.facebook.com/groups/platepalate/permalink/926562307398070/

Here's the recipe (using breadmaker but you may use hand or mixer to need):
Dough Ingredients
1 cup (240 ml) of milk
3.5 cups (437.5 grams) of bread flour
50ml coconut oil (or any oil or melted butter)
1/4 cup (50 grams) of granulated sugar
1/2 teaspoon of salt
2.5 tsp of instant dry yeast (I used 1 pkt of SAF)
1 egg
1/2 cup or 1 cup of mashed potatoes (I used 1 medium russet potato, boiled and mashed. This comes to 1 cup. Due to time constraint, I used the microwave to zap the potato on high for 3 min and then mashed it)

Fillings
1/4 cup (50 grams) of castor sugar
1/4 cup (50 grams) of brown sugar
1.5 tablespoon of cinnamon powder
50 grams of butter, softened 

Others (optional)
2 tbsp of cream or milk for egg washing

Instructions
1. Put all the dough ingredients into your BM as per your BM method. For my Kenwood, I mix the liquids in a big bowl first (milk, oil, egg, as well as mashed potatoes), then pour into the BM. 
2. Pour your flour. 
3. Put salt in a corner and sugar in another corner. 
4. Make a well with your finger in the center of the flour and pour in yeast. 
5. Select Dough function (#10). 
6. One and half hour later, take out the dough, punch it down, and using a rolling Pin, roll into a large flat rectangle. 
7. Spread melted butter onto the flattened dough. 
8. Spread the melted butter on the dough. 
9. Sprinkle the cinnamon sugar on.
10. Roll up the dough. Cut into rolls (approx 3-fingers width). 
11. Place the rolls in a greased tray, cover with damp cloth and let it proof in a warm place for at least 30mins. (I proofed mine in my preheated 50C) oven with door open. 
12. Turn the oven to 170C. Remove the tray and brush on the glaze (optional). Bake the buns for 25-30 minutes. If the top is getting brown, put aluminum foil to prevent burnt top. 

Note :
So far, any bread I made with mashed potatoes always produce fluffy bread, without needing overnight proofing. But if you put too much mashed potatoes, the bread may turn out too spongy. Hence for me, with 3.5 cups flour, I ensure my mashed potatoes quantity do not exceed one full cup.