Combine 1 3/4 cups of warm water, 1 tablespoon of sugar and 1 packet of active dry yeast and allow it to rest in a warm place for 15 minutes
Add 5 cups of flour, 1 tablespoon of salt, 1/2 cup of olive oil and the bloomed yeast mixture into the bowl of a stand mixer
Mix on low with a dough hook attachment until the ingredients are fully incorporated
Increase the speed to medium and knead for 5-6 minutes
Add 1 tablespoon of flour at a time if the dough is really sticky
Transfer the dough onto a floured work surface and knead by hand a few times
Oil a large bowl and transfer the dough into the bowl
Cover the bowl tightly with plastic wrap and a kitchen towel and allow the dough to rest in a warm place for 1 hour or until the dough has doubled in size
Add 1/2 cup of olive oil into a 9"x13"cake pan and transfer the dough into the pan
Begin stretching the dough out toward the corners of the pan with the tips of your fingers
Flip the dough over, so that all of the dough is coated with olive oil
Continue to press the dough out until it has fully filled the panĀ
Using the tips of your fingers, press holes throughout the dough
Cover with a kitchen towel and allow the dough to rise for 60 minutes
Preheat the oven to 425 degrees
Sprinkle dried parsley flakes, 1 cup of pecorino romano and a pinch of sea salt over the surface of the dough
Cut the prosciutto into ribbons and twist each ribbon a bit. Place the prosciutto all over the surface over the dough
Bake at 425 degrees for 25-28 minutes
Once the focaccia is golden brown, transfer it onto a heat proof surface and allow it to rest for 5 minutes in the pan
Transfer the focaccia out onto a cooling rack and allow it to cool fully before slicing