Heat water in microwave for about 2 minutes, or until warm but not hot (don't kill the yeast!)
Pour water in very large bowl--I use stainless steel restaurant style mixing bowl.
Add 3 to 4 cups of flour, sprinkle yeast over that, then mix together.
Keep stirring and adding flour until mixture is a soft dough, then add rosemary leaves, stripped off stalks. Add flour and mix until your spoon gets bogged down, then start adding flour a little at a time and begin to knead it. Don't make this too stiff--if it's a little sticky it's okay. Just keep kneading about 10-14 minutes until it is roughly a ball, and keep sprinkling on the flour and also a little olive oil if you want.
Splash on some more olive oil and let it rest for 30 minutes.
Pour 1/4 " of olive oil on cookie sheet. Pinch off a ball of dough the size of a large orange and flatten in the olive oil, then flip over. Depending on the size of your cookie sheet, you should have room for at least two of these. Flatten, then sprinkle with more rosemary leaves (and other herbs if you like). Sprinkle with coarse salt. You can put this first sheet in a cold oven, and turn on oven to 400 degrees and bake for about 15 or 20 minutes, until golden brown on bottom and top.
Right after first batch is put in the oven, get out another cookie sheet and repeat, but leave off the salt until the first batch comes out. Sprinkle and put it in, and keep on until all dough is used up. I reuse the sheets as long as they are cool, and all you have to do is pour in more olive oil.
This makes 6-8 flat loaves and they freeze wonderfully, in heavy duty foil. I put two to a package.