Prepare the dough:
In a glass bowl, combine the flour and kosher salt. Set aside.
In a separate glass measuring cup, mix together the warm water, instant yeast, and sugar. Let it sit for about 1 minute until slightly foamy.
Stir the yeast mixture into the flour with a wooden spoon until the dough just comes together.
Cover the bowl with plastic wrap and place in the refrigerator for 8 hours, or overnight.
Shape and rise the dough:
Remove the dough from the refrigerator.
Drizzle olive oil into an 8-inch round cake pan, and place the dough in the center, tucking the ends underneath.
Cover with plastic wrap and allow the dough to rise at room temperature for 2 hours.
Prepare and bake the focaccia:
Preheat the oven to 450°F (230°C).
Once the dough has risen and fills the pan, drizzle additional olive oil over the top.
Using your fingers, press holes into the dough, making sure to press down to the bottom but not through the dough.
In a small bowl, combine the minced garlic, grated Parmesan, and Italian seasoning.
Sprinkle the garlic-Parmesan mixture evenly over the dough and top with Maldon flaked sea salt.
Place the pan in the oven, reduce the temperature to 425°F (220°C), and bake for 22-24 minutes or until the focaccia is golden brown.