Slice a16.5 oz. tube of refrigerated cookie dough into 1/2-inch slices, and place them on a round Pyrex pizza dish. (If you don't have a pizza dish, just place the dough slices in a circle in a baking pan.) Use your fingers to press the dough slices together evenly, forming one big cookie. Make sure that the thickness of the cookie is uniform throughout. Bake your large cookie at 350 degrees for 10 to 12 minutes. When it is done, remove it from the oven and let it cool completely. (You may put it in the refrigerator to cool quickly, after it has cooled a bit initially.) When your big cookie is cool, spread the entire 15 oz. can of vanilla frosting evenly on top of it. Place your washed and dried pint of blackberries carefully at the center of the pizza, on top of the frosting in a circle. Next, place your 2 pints of raspberries in a ring around the blackberries on top of the frosting. Done!!! It's that quick and easy!!! Cover with plastic wrap and refrigerate until ready to use. When ready to serve, cut the "pizza" into wedges, and serve them on nice serving plates. Have a safe and happy 4th of July holiday!