In a large mixing bowl, combine warm water, sugar, and active dry yeast. Stir gently and let it sit for about 5-10 minutes until frothy.
Add the flour, salt, and black pepper to the yeast mixture. Mix until a shaggy dough forms.
Pour in the olive oil and knead the dough in the bowl or on a lightly floured surface for about 5-7 minutes until smooth and elastic.
Place the dough in a greased bowl, cover with a damp cloth, and let it rise in a warm place for about 1 hour or until doubled in size.
Once risen, punch down the dough to release air. Transfer it to a greased baking sheet (about 13x18 inches) and stretch it out to fit the pan.
Cover the dough again and let it rise for another 30 minutes.
Preheat your oven to 425°F (220°C).
After the second rise, use your fingers to create dimples all over the surface of the dough. Drizzle with olive oil and sprinkle the minced garlic, Parmesan cheese, and optional rosemary over the top.
Bake the focaccia in the preheated oven for 20-25 minutes or until golden brown.
Remove from the oven and let it cool slightly before slicing. Serve warm or at room temperature.