Preheat the oven to 475˚F.
In a large bowl, combine the flours, salt, yeast, and garlic salt; stir well to combine.
Stir in 1/4 cup of warm water, mix, then pour in another 1/4 cup; continue to mix. Pour the rest of the water, if needed, until all of the flour is absorbed.
Turn the dough out onto a lightly floured surface and knead for 1 minute.
Lightly oil a large bowl, place the dough in the bowl and turn to coat with the oil.
Cover with a kitchen towel and let rise in a warm place for about 30 minutes. I always put it on top of my warm stove, and the rise is done within 20 minutes.
Take the dough and knead it again, briefly, on a lightly floured surface.
Then, roll the dough into a rectangular shape, about 1/4 inch thick, and place it on a lightly greased baking sheet.
Dimple the dough with your index finger.
Brush the dough with olive oil and sprinkle with garlic powder, oregano and rosemary.
Bake it for 10 to 20 minutes, depending on desired crispness.
Remove from the oven and let it cool for 10 minutes.
With a sharp knife, slice the focaccia into wedges and serve it with garlic sauce, cheese sauce, or any dipping sauce of your choice. You can also cut it into squares and make little bite-sized sandwiches.