In a medium sized jug, add the warm milk and swirl through 1 tablespoon of sugar. Sprinkle yeast over top and give a light whisk. Allow the yeast to flourish and foam, roughly 5 minutes. After, whisk through the eggs until well combined.
While yeast is flourishing, prepare dry ingredients by adding and mixing the flour, salt and remaining 4 tablespoons of sugar together in the bowl of a stand mixer fitted with a dough hook.
Pour in the milk mixture and on a medium speed, begin to mix into flour. Dice butter into cubes and add to mixture one at a time, making sure each cube is well incorporated. When all the butter has been added, turn the kneading speed up to medium-high for 5-6 minutes. The dough should now be nice and soft and easy to handle.
Grease a medium sized bowl with melted butter and place rounded dough into the bowl. Cover with cling wrap and leave to rise in a warm area for about 1 hour or until it doubles in size.
When risen, turn dough out onto a floured surface and using a rolling pin, roll dough out into a rectangle about 1cm thick. Beat together filling ingredients and spread evenly over the dough.
Roll dough up tightly starting from the long side before using a sharp knife or floss to cut/slice 9 even segments. Place inside a lined or grease 20-22cm square baking tin, cover and return to a warm place to complete its final rise. Roughly 1 hour or until rolls double in size again.
While dough is rising, preheat the oven to 180°. When the dough is ready, bake for 25-30 minutes until baked through and golden on top. Allow to cool before covering in frosting.
To make the frosting, beat together the frosting ingredients until well combined and fluffy. Spread over top of baked rolls and finish off with a sprinkle of lemon zest and crumbled biscuits pieces (optional). Enjoy.