In a large bowl, whisk together warm water, sugar, and yeast. Let it sit for 5 minutes until foamy. This tells you the yeast is alive and ready to do its job.
Add the flour, salt, and olive oil. Stir until a sticky dough forms. No kneading needed; focaccia dough should feel wet.
Cover the bowl with plastic wrap or a clean towel and let it rise in a warm spot for 1 hour or until doubled in size.
Preheat the oven to 400 degrees F. Grease a 12-cup muffin tin with olive oil.
Spoon equal portions of the dough into each muffin cup. Use oiled fingers to gently press the dough down and create small dimples.
Mix olive oil, garlic, and rosemary. Brush generously over each muffin.
Sprinkle with flaky salt and black pepper if desired.
Bake for 18 to 20 minutes or until golden brown.
Let them cool for 5 minutes before removing from the pan.