Make starter simply by mixing bread flour, water, yeast, and honey. Cover and let rest on the countertop for about 5-6 hours.
After it has tripled in volume and lots of bubbles on top, mix in the rest of the flour and the ice cold water and salt. Finally, add the extra virgin oil, no kneading required.
Cover and let rest for 30 minutes.
Mix all the ingredients well and set aside. Half of the mixture will be used on the Focaccia dough. And the remaining goes on top.
Then do 1 round of stretch and folds, and add half of the cinnamon sugar mixture so it's incorporated and the pieces of butter : sprinkle some cinnamon sugar mixture and some butter pieces, then grab the dough stretching it out and then fold towards the center. Sprinkle some more cinnamon sugar, then fold.
Flip seam side down and shape into a ball.
The dough will be very wet and sticky.
Place in the fridge overnight.
The day after, take dough out of the fridge and leave at room temp for 2.5-3 hours. Then, divide and shape the dough into 24 balls.
Grease muffin tin with butter. Sprinkle some of the cinnamon sugar mixture (keep some for the top when dimpling).
Place the dough balls on it and gently. Let rest for 60-90 minutes.
Preheat oven at 425°F.
Make icing:
Mix all the ingredients adding the milk slowly until desired consistency
Grease your fingertips, sprinkle the rest of the cinnamon sugar among the 24 muffins and dimple. Bake on bottom rack for about 10 minutes, then move on the middle rack and finish baking until golden crispy on top (about 5 minutes).
Take them out of the oven and leave in the pan for about 2-3 minutes, then place in a big bowl and drizzle with icing while still warm.
Enjoy!