If you are looking for an impressive yet casual dessert, appropriate for a summer birthday celebration or a backyard barbecue, one that uses summer fruit and is able to serve a dozen or more guests, look no further than slab pie.
“Slab” may not be the most appetizing word to describe a pie, but when you see one of these giant rectangular creations, crisscrossed with golden pastry and barely containing a bounty of juicy berries, you will fall in love. The technique is familiar: Instead of fitting pie dough into a round pan, you fit the dough into a rimmed baking sheet. Then you fill the bottom crust with sweetened fruit, top with strips of dough to create a lattice, and bake until bubbling. The result is twice as many servings of fruity, flaky dessert for the same amount of work.
If you are a fan of crust (and who isn’t?), this is the pie for you. In addition to an extra-thick bottom crust (necessary so the extra-large piece of raw pastry doesn’t tear as you transfer it to the pan), there are many inches of coveted double-thick edges, and four corner pieces for crust lovers to fight over.
Another reason slab pie is extra crispy/flaky: It has proportionately less fruit than regular pie, just enough to make a jam-like filling to sandwich the top and bottom crusts together. A regular 9-inch fruit pie contains about 5 cups of fruit. For a slab pie, about 8 cups of fruit in a 10-inch-by-14-inch pie is just right, producing a juicy pie that can still be cut into neat slices.
A lattice top gives slab pie a classic look, but there are other ways to vent a pie crust so the liquid can evaporate from the fruit while the pie bakes. Instead of cutting half your pie dough into strips for weaving, just roll it into another 12-inch-by-16-inch rectangle and slide it on top of the fruit. Trim and crimp the edges. Then use a sharp paring knife to cut small slits in the top crust of the pie.
MIXED BERRY SLAB PIE
Pie dough for 2 (9-inch) round double crust pies (about 2 1⁄2 pounds), chilled
4 cups blueberries
2 cups raspberries
2 cups blackberries
3 tablespoons cornstarch
1 teaspoon grated lemon zest
1⁄2 cup sugar plus more for sprinkling
2 tablespoons unsalted butter, cut into bits
1 large egg, lightly beaten
1. On a lightly floured countertop, roll out half the dough (if you are using store-bought dough, press two crusts together before rolling) to a 12-inch-by-17-inch rectangle. Transfer to a 10-inch-by-15-inch rimmed baking sheet. Cover with plastic wrap and refrigerate.
2. Line a rimless baking sheet with parchment paper. On the floured countertop, roll out the remaining dough to a 12-inch-by-16-inch rectangle. Use a fluted pastry cutter to cut the dough into 9 (1-by-16-inch) strips. Lay 4 of the strips lengthwise, 1 inch apart, on the lined baking sheet. Weave the remaining 5 strips in and out, crosswise to create the lattice top. Cover with plastic wrap and refrigerate for at least 30 minutes.
3. Preheat oven to 400 degrees. Arrange a rack in the lower third of the oven. Combine the berries, cornstarch, lemon zest, and 1⁄2 cup sugar in a large bowl, mashing some of the berries against the side of the bowl to release a little juice. Let stand, stirring occasionally, to dissolve the sugar.
4. Spread the berry mixture evenly across the chilled bottom crust. Dot with butter. Carefully slide the lattice top from the parchment to the pie. Trim the overhanging top and bottom crusts with scissors so they overhang the baking sheet by 1⁄2 inch. Fold the overhanging dough under and tuck it into the pan. Crimp the edges. Brush the top and edges of the dough with the egg and sprinkle with sugar.
5. Bake for 15 minutes, lower the heat to 375, and continue to bake until the crust is golden brown and the pie is bubbling, 45 to 50 minutes longer. Let cool on a wire rack to warm room temperature and serve warm. Or cool completely and serve at room temperature.
Makes 12 to 16 servings.