Start by combining the flour, instant dry yeast and salt in a bowl.
Using a microwave safe bowl, combine the buttermilk, butter, sugar, water and milk. Heat in the microwave on high for about 1 minute. Or place these ingredients in a pot and heat on the stove just until the butter starts to melt. The butter should still be in clumps and not totally melted. This should also apply if you are using the microwave. Do not allow it to boil or be too hot. If you are using a thermometer, the temperature of the heated mixture should read at about 125°F / 50°C before being added to the flour mixture.
Add this warmed milk mixture to the flour mixture. Using a spoon, mix to combine and turn out onto a board or counter top dusted with flour. Knead for about 4 minutes to form a soft dough.
Leave the dough to rest, covered on the board or counter top for 15 minutes.
After 15 minutes, roll out the dough to roughly a 20x15 inch / 50x40cm rectangular shape. Brush the dough with the filling and cut into 24 strips.
Roll each strip tightly and place on a greased 9x13 inch / 22x33cm baking pan.
Leave to rise in a warm, draft free area for 40 minutes. After 40 minutes, bake the cinnamon buns in a preheated oven of 356°F / 180°C for 15 to 20 minutes until baked.
Remove from the oven and allow to cool before covering with a glaze icing / frosting.