Activate the yeast. In a small bowl, combine warm water (about 110℉) and granulated sugar. Sprinkle the active dry yeast over the top and let it sit for 10-15 minutes until it becomes foamy.

Mix the dough. In a large mixing bowl, whisk together the flour and salt. Then, pour in the activated yeast mixture along with the olive oil. Stir everything together until the dough forms a stick dough ball. Rub the surface of the dough lightly with olive oil.

First rise. Cover the bowl with a damp tea towel or plastic wrap. Then, place it in the refrigerator for at least 12 hours.

Second rise. Grease a 9x13-inch baking pan and line with parchment paper. Then, pour 2 tablespoons of melted butter into the center of the pan. Using your fingers, gently deflate the dough by pulling it from the sides of the bowl and folding it toward the center. Do this several times. Then, place the dough into buttered pan. Cover and let it rise for 1 ½- 2 hours in a warm spot in your kitchen.

Make the brown butter. In a small saucepan, melt ½ cup butter over medium heat. Continue stirring until you notice a nutty aroma and the butter turns a golden-amber color. Remove it from the heat immediately to avoid burning. Allow it to cool for 10 minutes before using.

Make the cinnamon topping. Add the brown sugar and cinnamon to the browned butter, mixing until the sugar is dissolved.

Dimple the dough. Preheat oven to 450℉. Once the dough has risen for a second time, with wet fingertips, press deep dimples all over the surface. Then, drizzle the cinnamon-butter evenly over the dimpled dough.

Bake. Bake for 20-25 minutes, until the focaccia is golden brown. Let cool for 10 minutes in the pan, then transfer to a cooling rack.

Finish with vanilla icing. Combine the powdered sugar, milk, and vanilla extract. Mix until smooth. Then, drizzle the icing evenly over the warm focaccia. Slice into squares and enjoy!