In a large bowl, whisk together flour, yeast, sugar, and salt.
Add warm water, 2 tablespoons olive oil, garlic, and rosemary. Mix until a sticky dough forms.
Cover and let rise in a warm place for 45–60 minutes, until doubled in size.
Preheat oven to 400°F (200°C) and grease a 12-cup muffin tin with olive oil.
Divide dough evenly into muffin cups, filling about ¾ full.
Drizzle remaining olive oil over each portion and press dimples into the dough.
Sprinkle with rosemary, flaky sea salt, and Parmesan if using.
Bake for 18–22 minutes until golden brown.
These Garlic Rosemary Focaccia Muffins come out perfectly crisp on the outside and soft inside.