Mix together all the dough ingredients and knead briefly; 5-6 minutes by hand or in a mixer. Cover the dough and let it rise for 15 minutes. Remove it from the bowl, fold it over a few times to redistribute the yeast.
Pat the dough into a 10x15 inch rectangle on a lightly greased or parchment-lined baking sheet. Brush with olive oil and sprinkle lightly with coarse salt and rosemary. Cover with lightly greased plastic wrap, let rise in a warm place for about 30 minutes.
Just before baking, use your fingers to gently dimple the top of the dough. Bake the focaccia in a preheated 425 degree oven for 15-18 minutes, until golden brown. Remove from the oven and place it on a rack to cool slightly before serving.