Best-ever gooey, sticky cinnamon rolls

Method
Prep:45min  ›  Cook:25min  ›  Extra time:2hr15min rising  ›  Ready in:3hr25min 

1. Mix 300g caster sugar, cinnamon and pecans together in a bowl; set aside to be used as filling later.
2. Whisk yeast and warm water together in a separate bowl; sprinkle with 1 teaspoon sugar. Continue whisking until well incorporated. Set aside until yeast foams, 10 to 20 minutes.
3. Place warm milk, 125g sugar, 150g melted butter, salt, eggs and yeast mixture in a stand mixer; mix until all ingredients are incorporated. Add half of the flour; mix on medium until completely smooth, about 5 minutes. Transfer dough to a large bowl; knead the remaining 500g of flour into dough with hands until dough is slightly stiff and sticky, 10 minutes.
4. Transfer dough to a large greased bowl; cover bowl with cling film. Let dough rise in a warm place until doubled in size, about 1 1/2 hours.
5. Remove cling film from bowl and punch down dough. Set dough aside to rest for 5 minutes.
6. Roll dough out on a well-floured surface, forming a 38x50cm (15x20 in) rectangle. Brush entire rectangle of dough with about 125g of the melted butter; sprinkle with cinnamon-sugar filling. Tightly roll up dough, starting from a long end and pinch edges together to seal. Cut dough, using plain dental floss, into 15 to 20 slices.
7. Grease a 20x30cm (9x13 in) baking dish or Pyrex with remaining melted butter; sprinkle bottom of dish with 5 tablespoons caster sugar. Arrange cinnamon rolls snugly in the dish, then set aside to rise in a warm place for 45 minutes.
8. Preheat the oven to 180 C / Gas 4.
9. Bake rolls in the preheated oven until golden brown, 25 to 30 minutes. Remove and let cool slightly before icing.
10. Beat icing ingredients together in a bowl until smooth. Drizzle over warm cinnamon rolls.

Cook's note

If the icing is too thick to drizzle, add a touch more butter, one teaspoon at a time, until desired consistency is reached.