Place potatoes in a medium saucepan with enough water to cover. Bring to a boil, and cook until tender but firm, about 15 minutes. When the potatoes are done, remove from heat, and drain, reserving the potato water.
Pour the flour and 1 tablespoon of salt out onto a clean dry surface. Make a well in the centre, and use a ricer to rice the potatoes into the centre. Knead the flour and potatoes together as best you can, and then make another well in the centre. Dissolve the yeast in the potato water, then pour the mixture into the well. Knead the dough for about 10 minutes, or until dough is smooth, and no longer sticky.
Divide the dough into halves, and form into balls. Flour heavily, and cover with a few cloths to prevent drafts. Let the dough rise until doubled in size, about 2 hours.
Preheat the oven to 180 degrees C. Coat two large baking trays with olive oil.
Press the dough out evenly onto the baking tray. Press indentations into the sheets with your fingers every couple of inches. Spread a tin of tomato onto each sheet of dough evenly. Place the onion and anchovies onto the dough sheets, and press in lightly. Sprinkle with salt and oregano to taste. Drizzle lightly with olive oil.
Bake for 35 to 40 minutes in the preheated oven, or until bottom is browned. Let cool to room temperature, then cut into squares using a pizza cutter.
I made this recipe for my family and they love it. Even my father loves it, and it's hard to please my father when it comes to food. I wouldn't change a thing the recipe works well...Love it! - 29 Sep 2008
Everyone loved this recipe. My husband was not sure about focaccia but when he tasted it he was hooked. Dough was light and delicious. Not a fan of anchovies so just left them off. Ate one immediately and froze one for later. Will definitely make again. - 29 Sep 2008
This was soooooooo good! It looked, smelled and tasted like something from a top notch Mediterranean restaurant. I made it two days in a row; the second time, I added some chopped garlic along with the tomatoes, onion and anchovies. Absolutely amazing! Thanks so much! - 29 Sep 2008