The next time you are preparing for a party or potluck, you might consider a slab pie, or slices, as my mother used to call them. If you intend to make one, you will need at least one half-sheet pan, which as you will see in the store, always have the same dimensions (18 x 13 inches). The slab pie is not intended for a rectangular baking dish like the 9-by-13-inch guys that we buy all the time (no kitchen should be without one).
My mother used to make a slab pie with apples, which she called Apple Slices. She made them using the standard method: make a LOT of pie crust, lay it in the half-sheet pan and fill with apple slices. The apples are prepared in the usual way for apple pie, spiced and sweetened. Then she put a top crust over it and when it was cool, she would drizzle it with a simple butter frosting glaze. Discussing it brings back many memories of how much my father and brother loved it.
Your usual place to find a half-sheet pan in Tucson would be the local Walmart or Super Target stores; you can also find them in the Martha Stewart collection at Kmart. There isn't any reason to spend lots of money on something that is available everywhere. The only thing I look for is aluminum, so it won't rust on me. I appreciate the anti-aluminum information that is out there for cookware; I would never buy a set of aluminum pots and pans (even nonstick or anodized) but there isn't any harm in cookie sheets or bakeware that is not used every day.
This recipe below is for a slab pie of mixed berries. It is easy to plan for because you can get outstanding mixed berries in frozen form in Tucson's health-oriented markets like Sprouts and Whole Foods. Cascadian Farms is one organic brand that comes to mind, and those berries are little nutrition bombs containing all kinds of good fruit enzymes and phytonutrients.
MIXED BERRY SLAB PIE
For the crust:
8 cups all-purpose flour
1 cup sugar
2 teaspoons sea salt
4 sticks unsalted cold butter, cut into 1/2" pieces
3 large eggs
1/2 cup cold Water
For the filling:
1 pint container blueberries
1 pint container raspberries
1 pint container blackberries
1 cup granulated sugar
3 Tablespoons cornstarch
Cream for brushing top of pie
Powdered sugar to dust the pie
Preheat your oven to 400 degrees. Set aside two half-sheet pans. Use one for the slab pie, the other as a template.
Combine all the berries in a large bowl. In a medium bowl whisk together the pie filling sugar and cornstarch until well combined. Add the sugar mix to the berries and gently toss to coat. Set aside.
In a large bowl, whisk together the flour, sugar, and salt. Pinching with your fingers or using a pastry blender or food processor, mix the butter into mixture until no large pieces of butter remain and it has a crumbly texture. (This quantity may require preparing in batches; combine them in a large mixing bowl when the batches are ready.)
Whisk the eggs and cold water together. Make a well in the middle of the flour mixture and pour the egg mix into the well. Working from the center out, stir the egg and flour mixes until the dough holds together. If necessary adjust with a little additional flour or cold water if dough is sticky or if it is not holding together.
Divide the dough into two portions of one-third and two-thirds.
On a large floured surface, roll out the larger portion of dough to a 24"x19" rectangle, dusting the underside and top of dough with flour a few times while rolling out to keep dough from sticking.
Gently roll the dough around the rolling pin, then unroll it over the first sheet pan. Adjust the dough so it fits evenly in sheet pan. Dock the pastry by pressing in with a fork several times making small punctures across the bottom of the pastry. Layer in the berry mix. Set aside.
Roll out the 1/3 portion of the dough to just larger than 18 by 13 inches. Flip your second sheet pan upside down and gently press into dough. Use impression to cut the dough to size. Pick up the dough by rolling it around rolling pin, then unroll it over the slab pie to form the top crust.
Fold the dough from the larger bottom crust up and around to meet the top crust and gently pinch to form the seal. Brush the top and edges with cream. Using kitchen scissors or a knife, cut slits into top of the pie.
Place in the oven and bake 30-40 minutes or until the top is golden. Remove from oven and allow to cool. Dust with powdered sugar, slice and serve.
It would also be a lovely touch to make a lattice crust on a slab pie. In the case of the berries, their bright color and appealing juices will make a pretty contrast with the typical pie crust. If you would rather do this, simply roll out the second batch of dough to 18-by-13 inches (approximately) and cut it into strips to lay across the top of the pie. Brushing the lattice with cream will encourage browning and give the pie even more color.
This treatment also recommends itself to the cook who doesn't have two half-sheet pans, or who doesn't feel like buying two of them.