Mix together all of the dough ingredients in a medium-sized bowl, then knead --using your hands, a mixer, a food processor or a bread machine -- to form a smooth dough.
Place the dough in a greased bowl, cover, and allow it to rise for 1 1/2 hours, or until it's doubled in bulk.
Transfer the dough to a lightly floured or lightly greased work surface, knead it gently, then divide it in half. Round each half into a loose ball, and allow the balls to rest, covered, for 10 to 15 minutes. This allows the gluten in the dough to relax, making the focaccia easier to shape.
Roll one ball into a 10- to 12-inch circle. Place it on a lightly oiled baking sheet or pizza pan (or onto a peel dusted with cornmeal if you'll be baking the focaccia on an oven stone). Top the shaped round with the filling ingredients, spreading them evenly over the surface, and leaving about 1 inch crust bare around the edges. Roll the second half of dough into an equal-sized circle, then place it atop the filling. Press the edges of the dough together firmly to seal the two circles.
Cover the focaccia with a damp cloth, lightly greased plastic wrap or a proof cover. Preheat your oven to 425°F. Allow the focaccia to rise for 45 minutes, or until it's noticeably puffy. Just before placing it in the oven, dimple it (poke gentle indentations into it) with your fingers, brush it with 1 tablespoon olive oil, and sprinkle it with coarse salt and rosemary. Bake the focaccia for 30 to 35 minutes at 350.