Dissolve yeast into ½ cup lukewarm water. (110 degrees F.) Rest 10 minutes.
Add salt and 1 tablespoon of flour. Incorporate well.
Add 1 cup flour, mix. Add olive oil, half remaining water and half remaining flour.
Mix well with hands.
Add remaining water and flour. At this point you can put into mixer with dough hook, or food processor. If you knead by hand, slap down on counter several times and knead for 8 minutes or until the dough is very workable and soft.
Rest in oiled bowl with covered damp towel for two hours.
At end of this rising time, punch down, place on oiled baking sheet, stretch by hand to the edges, trying to keep a uniform thickness, especially in the corners.
Allow to rise for two hours
Using a wooden spoon, small ball or finger tip, make indentations.
Using pastry brush, carefully brush olive oil water mixture over top. Top with peaches.
Put in oven, reduce heat to 400 and bake for 15 minutes.
Top with tablespoon finely chopped rosemary and bake for another 7-8 minutes.
When you take it out of the oven, the top will be a little crispy. As the focaccia cools, it softens up and will become springy.
You can now add in some more fresh rosemary if you want and drizzle olive oil or serve with an herbed dipping oil.