2¼ cups (288g) all-purpose flour, plus more for kneading
1½ teaspoons (4 ½ g) dry instant yeast
1½ teaspoons (9g) granulated sugar
1½ teaspoons (9g) kosher salt
¾ cup (177ml) very warm tap water
½ cup (120ml) olive oil, divided
1 cup (150g) coarsely grated parmesan
For the garlic, heat oven to 400F (205C). Oil a large bowl; set aside.
Trim ¼-inch (1/2 cm) off top of garlic bulb to expose cloves. Place on a piece of aluminum foil and drizzle with olive oil and season with salt. Wrap the bulb tightly in foil and bake until softened, 40 to 45 minutes. Set aside to cool.
For the focaccia, combine 2¼ cups (288g) flour, instant yeast, sugar and salt in a large bowl.
Make a well in the middle then pour in water and ¼ cup (60ml) of olive oil and stir with a wooden spoon to form a shaggy dough.
Turn onto a well-floured work surface, squeeze the garlic out of the papery skin onto the dough and knead for 6 minutes until soft and springy, adding more flour as needed to create a soft, but not sticky dough.
Shape dough into a ball and place in prepared bowl. Cover the bowl with plastic wrap and a clean kitchen towel and allow the dough to rise in a warm place until doubled in size, about 1 hour.
Pour remaining olive oil into a 9x13-inch (33x23 cm) baking pan and set aside.
Turn dough into pan and press to nearly fill pan, poking fingers into dough to stretch gently. Cover with plastic wrap and kitchen towel and allow it to rise in a warm place, until almost double in size, about 45 minutes to 1 hour.
Heat oven to 425F (218C). Scatter loaf with parmesan and bake until golden brown, about 20 to 22 minutes.