Heat oven to 425°. On a lightly floured work surface, roll the pie dough into a rough 11 x 16-inch rectangle. Fit dough into a 10 x 15-inch rimmed baking sheet, folding over edges and press to form a crust. Pierce the entire surface of the dough with a fork. Bake the dough for about 6 minutes or until lightly golden. Cool completely on a wire rack.
Meanwhile, cut tomatoes into 1/2-inch thick slices and drain between several layers of paper towels.
Stir together the yogurt, ricotta, garlic, breadcrumbs and 1/2 teaspoon of the salt and 1/4 teaspoon of the pepper. Spread over bottom of crust. Cover the yogurt layer with tomatoes, arranged so they are touching but not overlapping. Drizzle tomatoes with the olive oil, and sprinkle with remaining 1/2 teaspoon salt, 1/4 teaspoon pepper, basil and prosciutto.
Bake for 10 minutes. Reduce the oven temperature to 350°and bake for 10 minutes. Cut into squares and serve immediately.