In a mixing bowl, combine warm water and sugar, then sprinkle active dry yeast over the top and let it sit for about 5 minutes, until foamy. In a stand mixer, mix 1 cup of all-purpose flour and salt, add olive oil, and gradually incorporate the yeast mixture. Continue adding the remaining flour until the dough pulls away from the sides of the bowl and is slightly sticky.

Preheat your oven to 220°F (104°C) and then turn it off to create a warm environment for the dough. Grease your skillet with olive oil. Roll the dough out to fit the skillet size, stretching it to the edges. Cover it with a towel and place the skillet in the warm oven for 20 minutes to allow the dough to rise and double in size.

After the dough has proofed, remove the skillet from the oven and preheat it to 400°F (204°C). Gently poke holes in the dough with the handle of a wooden spoon to create dimples. In a small bowl, mix melted butter, grated Parmesan, and Italian seasoning; brush half of this mixture generously over the dough to infuse flavors.

Carefully place the skillet in the oven and bake the Skillet Focaccia Bread for about 20 minutes, or until the crust is golden brown and crispy. Once done, remove it from the oven and brush the remaining butter mixture on top. Allow the bread to cool slightly in the skillet before slicing and serving warm.