In a mixing bowl, combine warm water with granulated sugar. Sprinkle active dry yeast on top and let it sit for 10-15 minutes until frothy.

In a separate bowl, whisk together bread flour and salt. Pour in yeast mixture and olive oil, stirring until a sticky dough forms.

Lightly oil the dough surface, cover with a damp towel, and refrigerate for at least 12 hours.

Prepare a greased baking pan, gently deflate the dough, and spread into the pan. Cover and let rise in a warm place for 1.5-2 hours.

In a saucepan, melt unsalted butter over medium heat until golden brown and nutty, about 5-7 minutes. Cool slightly.

Mix light brown sugar and cinnamon in a small bowl. Add cooled brown butter and stir until combined.

Preheat oven to 450°F. Dimple the dough and drizzle the cinnamon topping evenly.

Bake for 20-25 minutes until golden brown and crisp.

Cool for 10 minutes, then mix icing ingredients and drizzle over the focaccia.