This patriotic pie is large and portable, making it ideal for holiday barbecues and gatheringsTake advantage of summer’s berry bounty with this impressive patriotic slab pie, perfect for a Fourth of July dessert or Memorial Day BBQ treat. The pie is served straight out of the baking pan, which makes transporting it to your holiday gathering a breeze. Start by rolling out refrigerated piecrusts, or a double batch of our Best Basic Pie Crust Dough. Fit the dough into a 13- by 18-in. rimmed baking pan and press edges over the rim. Chill the baking sheet along with stars and stripes cut from the other half of the dough. Make two fillings: blueberries mixed with sugar, cornstarch, and lemon juice for the upper left square; and strawberries and raspberries with the same mixture for the stripes. Gently spread the two fillings into their appropriate spots within the crust and top with the cutouts. Brush an egg and cream wash on the crust and sprinkle with turbinado sugar. Bake and let cool for at least 2 hours before serving.