Place a rack in the middle of the oven. Preheat the oven to 400 degrees F. Grease a 9-inch spring-form pan and line the bottom with parchment paper. Gently roll the puff pastry out on a clean surface to 1/4 inch thickness. Press the pastry inside the pan and up the sides of the pan. It is OK if the pastry does not go all the way up the pan (see above photos). Transfer to the fridge and chill while you prepare the batter. In a medium-sized mixing bowl, beat together the cream cheese and sugar on medium speed, scraping down the sides of the bowl until very smooth and creamy, about 2 minutes. Add the eggs, 1 at a time until the eggs are fully incorporated. Scrape down the sides of the bowl, then reduce the mixer speed to medium-low. Add cream, vanilla, and salt, and beat until combined, about 30 seconds. Sift the flour into the batter, then beat again to combine, about 30 seconds. Pour the batter into the prepared pastry-lined pan. Gently sprinkle the blueberries over the batter, some will sink. Gently fold the corners the pastry over the berries. Sprinkle the top of the cake with 1-2 tablespoons granulated sugar.Transfer to the oven and bake for 55-65 minutes, until deeply golden brown on top and still very jiggly in the center. Let the cake cool 5 minutes, then unmold. Let cool completely. Slice into wedges and serve at room temperature or chilled. I like room temp best.