Slab pie is a feat of baking ingenuity. The impressively large pie is prepared in a baking sheet rather than in a pie plate and can be cut into 24 easy-to-pick-up squares, making pie a big-party possibility. As with other fruit slabs, the filling for apple slab pie is thickened to a consistency that ensures neat slicing. And slab pie's flat top is perfect for holding a sweet glaze. But rolling out the dough to cover both the bottom and top of this mammoth pie is not without challenges.
We increased the proportions of our all-butter pie dough to create a large-scale recipe specifically for slab pies. Rather than roll the dough into really big rectangles that were bound to tear as we transferred them to the pan, we rolled out four smaller rectangles (two for the bottom crust and two for the top), overlapping them slightly and sealing them at their seams with water. Tapioca thickened the filling, but another helpful step was tossing the apples with sugar and letting them sit until some of their juices drained.
Not wanting that flavor to go to waste; we reduced the apple juice and stirred it into our confectioners' sugar-based glaze. Good choices for tart apples are Granny Smiths, Empires, or Cortlands; for sweet, we recommend Golden Delicious, Jonagolds, or Braeburns. You will need two 18 by 13-inch rimmed baking sheets for this recipe. You can toss the apple mixture in step 4 in two bowls if it doesn't fit in one.
Apple Slab Pie
- 2 recipes Slab Pie Dough (below)
- 3 1/2 pounds Granny Smith apples, peeled, cored and sliced 1/4-inch thick
- 3 1/2 pounds Golden Delicious apples, peeled, cored and sliced 1/4-inch thick
- 1 cup (7 ounces) granulated sugar
- 1/2 teaspoon table salt
- 6 tablespoons instant tapioca, ground
- 2 teaspoons ground cinnamon
- 5 tablespoons lemon juice (2 lemons), divided
- 1 tablespoon unsalted butter, softened
- 1 1/4 cups (5 ounces) confectioners' sugar
1. Line rimmed baking sheet with parchment paper. Roll each dough square into 16 by 11-inch rectangle on floured counter; stack on prepared sheet, separated by additional sheets of parchment. Cover loosely with plastic wrap and refrigerate until dough is firm but still pliable, about 10 minutes.
2. Using parchment as sling, transfer 2 chilled dough rectangles to counter; discard parchment. Spray second rimmed baking sheet with vegetable oil spray. Starting at short side of 1 dough rectangle, loosely roll around rolling pin, then gently unroll over half of long side of prepared sheet, leaving about 2 inches of dough overhanging 3 edges. Repeat with second dough rectangle, unrolling it over empty side of sheet and overlapping first dough rectangle by 1/2 inch.
3. Ease dough into sheet by gently lifting edges of dough with your hand while pressing into sheet bottom with your other hand. Brush overlapping edge of dough rectangles with water and press to seal. Cover loosely with plastic and refrigerate until dough is firm, about 30 minutes.
4. Meanwhile, adjust oven racks to lower-middle and lowest positions and heat oven to 375 degrees. Toss apples, granulated sugar, and salt together in large bowl. Let sit, tossing occasionally, until apples release their juices, about 30 minutes.
5. Working in batches, drain apples thoroughly in colander set over bowl; transfer to another large bowl. Reserve 3/4 cup of juice; discard remaining juice. Whisk tapioca and cinnamon together in small bowl, then add to apples along with 3 tablespoons lemon juice and toss to combine. Spread apple mixture evenly over chilled dough-lined sheet.
6. Using parchment as sling, transfer remaining 2 dough rectangles to counter; discard parchment. Overlap longer sides of dough rectangles by 1/2 inch, then brush overlapping edge with water and press to seal. Starting at the short side of joined dough rectangle, loosely roll dough around rolling pin, then gently unroll over top of filling, starting at short side of sheet.
7. Trim overhang to 1/2 inch beyond edge of sheet. Pinch edges of top and bottom dough firmly together. Tuck overhang under itself; folded edge should rest on edge of sheet. Crimp dough evenly around edge of sheet. Cut 2-inch slits at 2-inch intervals in top of dough.
8. Place large sheet of aluminum foil directly on lower rack (to catch any bubbling juices). Place pie on upper rack and bake until crust is deep golden brown and juices are bubbling, 1 to 1 1/4 hours, rotating sheet halfway through baking. Let pie cool on wire rack until filling has set, about 2 hours.
9. While pie is cooling, bring reserved apple juice to simmer in small saucepan over medium heat and cook until thickened and reduced to 1/4 cup, about 6 minutes. Off heat, stir in butter and remaining 2 tablespoons lemon juice. Let mixture cool slightly, about 10 minutes, then whisk in confectioners' sugar until combined. Brush glaze evenly over pie and let sit for 10 minutes. Serve.
Slab Pie Dough
(Makes one 18 by 13-inch single crust)
- 24 tablespoons (3 sticks) unsalted butter, divided
- 2 3/4 cups (13 3/4 ounces) all-purpose flour, divided
- 2 tablespoons sugar
- 1 teaspoon table salt
- 1/2 cup ice water, divided
1. Grate 5 tablespoons butter on large holes of box grater and place in freezer. Cut remaining 19 tablespoons butter into 1/2-inch cubes.
2. Pulse 1 3/4 cups flour, sugar and salt in a food processor until combined, two pulses. Add cubed butter and process until homogeneous paste forms, 40 to 50 seconds. Using your hands, carefully break paste into 2-inch chunks and redistribute evenly around the processor blade. Add remaining 1 cup flour and pulse until mixture is broken into pieces no larger than 1 inch (most pieces will be much smaller), 4 to 5 pulses. Transfer mixture to bowl. Add grated butter and toss until butter pieces are separated and coated with flour.
3. Sprinkle 1/4 cup ice water over mixture. Toss with a rubber spatula until mixture is evenly moistened. Sprinkle remaining 1/4 cup ice water over mixture and toss to combine. Press dough with spatula until dough sticks together. Using spatula, divide dough into 2 equal portions. Transfer each portion to sheet of plastic wrap. Working with 1 portion at a time, draw edges of plastic over dough and press firmly on sides and top to form compact, fissure-free mass. Wrap in plastic and form into 5 by 6-inch rectangle. Refrigerate dough for at least 2 hours or up to 2 days. Let chilled dough sit on counter to soften slightly, about 10 minutes, before rolling. (Wrapped dough can be frozen for up to one month. If frozen, let dough thaw completely on counter before rolling.)
Looking for more guidance? Watch the video below! Elle Simone walks through the ins and outs of slab pie.