Defrost frozen pastry in fridge for 30 minutes. 1. Preheat over to 400° F. 2. Prepare the crust: Remove the pastry from the package and roll out on a floured board to a 10x14 rectangle. Brush excess flour off and place on a parchment-lined or nonstick cookie sheet. Chill in refrigerator while peaches are being prepared. 3. Wash, peel, core and halve the peaches. Cut the peach halves into ?¼-inch slices, placing them into a nonreactive bowl. Add the lime juice and zest and the sugar and cinnamon, and mix carefully but well using your impeccably clean hands. Let sit for about 15 minutes. 4. Leaving a 1?½-inch border all around, carefully arrange the peach slices, draining them through your fingers as you place them onto the center of the dough, scattering the blueberries as well. Add the remaining juices carefully to the center of the tart. Remember, you dont have a crust wall yet and you dont want the juices to leak out. Dot the filling with butter. 5. Fold the edges of the pastry over about 1?½ inches toward the peach- blueberry filling, covering a bit of the fruit. Brush the turned pastry with some milk. 6. Mix the granulated sugar and cinnamon well. Sprinkle the mixture evenly over the milk-brushed crust. 7. Place in preheated oven on bottom rack. Reduce heat to 350° F. and bake for 45 minutes to one hour.