Put the pieces of potato in the small pot, and add enough water to cover the potato. With the lid on, bring to a boil over high heat. Reduce to medium and cook until fork tender. Remove the potato pieces, reserving the water. Mash the potato so that you have no lumps and measure ¼ cup of the potato. Measure 1 cup of the potato water. If you have less than 1 cup of water, add enough to make 1 cup. Water should be warm, about 110° to 115° F.
In the large mixing bowl, add the water, butter, eggs, potatoes, salt, sugar, 2 cups flour, and the yeast. Mix until smooth. Stir in the raisins and just enough remaining flour to form a soft dough, not dry. Turn the dough out onto a floured surface and knead until smooth and elastic, about 6-8 minutes. Place in the lightly greased bowl and spritz some cooking spray on the top of the dough. Cover and let rise in a warm place until doubled, about 1 hour.
Punch dough down. Turn onto a lightly floured surface and divide into eight pieces. Shape each piece into a ball. Place dough balls in the greased 10-inch springform pan. Cover and let rise until doubled, about 30 minutes.
While the dough is rising, preheat the oven to 350° F/175° C.
Uncover the risen dough and place the pan in the preheated oven. Bake for 25-30 minutes or until golden brown. Remove sides of pan. Place bread on a wire rack to cool.
If you use active dry yeast, you will need to proof it before mixing. Mix the yeast with the water in the mixing bowl and stir until the yeast is dissolved. It should start to bubble, letting you know it’s ready.If you decide to divide the dough in half, use two 8-inch springform pans.