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Blackberry Slab Pie to Feed a Crowd

When you need to feed a crowd, Slab Pie is the way to go. This Blackberry Slab Pie has a flaky pastry crust filled with lightly sweetened blackberries and a whisper of lemon.

A closeup shot of a  pie

What is a slab pie?

Good news! A slab pie is a pie that feeds 3x as many people as a regular round pie. Or, no judgement, feeds the same number of people 3x as much pie. Either way, it is an established fact that more pie is always a good thing.

So when you want to feed a crowd, or you just really love pie, this Blackberry Slab Pie is just the ticket. Not only is it supersized, with it’s chunky lattice top it’s incredibly pretty. I literally got oohs and ahhs when I took it out of the oven at a get-together.

Scroll through the step-by-step process photos to see how to make a slab pie:

a square of pie dough on a wooden table
Square up the dough with your hands.
Unrolling pie dough into a pan
Unroll the dough into the pan
cutting pie dough into strips for lattice pie crust
Cut the dough into strips to make the lattice
weaving a lattice top for a blackberry slab pie
Weave the strips into a lattice top.
a hand folding the edge of a pie crust
Fold the edge of the dough to form the crust.
an unbaked slab pie
Sprinkle the pie with sugar for a crunchy crust.
a closeup image of bubbling pie juices
Bake until the juices are bubbling all the way in the center.

Tips for Making Blackberry Slab Pie:

  • You can use fresh or frozen blackberries.
  • Make the pie dough the day before and let it rest in the refrigerator overnight or at least 3-4 hours. This not only relaxes the gluten in the dough, it allows time for the water to hydrate the flour.
  • You will need a triple batch of pie dough to make a 1/2 sheet slab pie. I mixed the dough all at once in a really big bowl. If you find it difficult to mix a large triple batch you can mix the recipe in three separate batches.
  • Watch this video to see how to weave a lattice crust.
  • A 1/2 sheet pie will feed about 24-30. You can make half the recipe and bake it in a 1/4 sheet pan for a smaller gathering.
  • Make sure you bake the pie until the juices at the very center are bubbling, otherwise the cornstarch will not activate to thicken the juices in the pie.
  • I like to sprinkle the crust with Demerara sugar for a crunchy finish. Granulated sugar can be used as a substitute. Because the dough is not very sweet, that little hit of sugar at the top is the perfect finish.
  • I like to serve this pie slightly warm. A scoop of vanilla ice cream would not be out of place.
  • Store the pie at room temperature. You can rewarm leftovers in the oven before serving.
A half sheet pan pie with a lattice crust on a wooden table.
A closeup shot of a piece of blackberry pie with a fork on a glass plate.
A closeup shot of a bite of pie in the end of a fork.

Got blackberries? You should try this amazing Blackberry Sorbet.

If you love this recipe please consider leaving a five star review!

a slice of berry pie on a glass plate

Blackberry Slab Pie

Yield: 24 portions
Prep Time: 1 hour
Baking Time: 45 minutes
Total Time: 1 hour 45 minutes

When you need to feed a crowd, Blackberry Slab Pie is the way to go. A flakey pastry crust is filled with barely sweetened blackberries and a whisper of lemon. The recipe can be halved for a smaller crowd.


  • 9 cups (3 pounds,1.36kg) fresh or frozen blackberries
  • 1 1/4 cups (10 oz, 280g) granulated sugar
  • 1 lemon, zested and juiced
  • 1/2 cup (3 oz, 85g) corn starch
  • pinch of salt
  • 3x batch Perfect Pie Dough (or your favorite recipe/product)
  • 1 egg for egg wash
  • Demerara sugar for topping


  1. Make the pie dough according to the recipe and chill at least 2-3 hours or overnight.
  2. Line a 1/2 sheet pan with parchment paper or a silicone baking mat. Divide the pie dough into 2 equal pieces. If the dough is very crumbly, knead a few time to bring it together.
  3. On a lightly floured surface, roll one portion of the dough to a 1/8" thick rectangle at least 20"x16". You can roll a little bigger to get the right thickness. Roll the dough onto the rolling pin to transfer it to the prepared pan. Sprinkle a light layer of flour over the dough in the pan.
  4. Roll the other piece of dough to a 1/8" thick rectangle at least 24" long (about 18" wide). Sprinkle flour over the dough and fold in 1/2, sprinkle with flour and fold again. Place the folded top crust into the pan. Put the pan in the refrigerator to chill while you prepare the filling.
  5. Toss together the blackberries, sugar, lemon zest, lemon juice, corn starch and salt.
  6. Remove the folded top crust from the pan then pour the berries into the crust. Evenly distribute any clumps of sugar over the berries.
  7. Unfold the top crust. Use a pizza cutter or sharp knife to cut along the long side of the rectangle to even out the edge. Use a ruler to mark 2" increments across the dough. Cut the dough into 2" wide strips. Lay 5 strips, long-ways, evenly spaced over the pie filling. Cut the remaining strips in 1/2 so they are 12" long.
  8. Watch this video to see how to weave a lattice crust. Trim all the top strips so they are just touching the edge of the pan. Trim the bottom crust to about 1/2" over the edge of the pan. Egg wash around the edges. Fold the bottom crust over to enclose the stripes. Use your fingers or a fork to crimp the edges. Egg wash the entire pie and sprinkle with Demerarra or granulated sugar. Chill the assembled pie for 30 minutes.
  9. While the pie chills, preheat the oven to 375°F. Bake the pie on the bottom rack of the oven until the juices in the middle are bubbling and the crust is golden brown, about 45 minutes.
  10. Serve slightly warm or room temperature.


To work ahead make dough and chill. The dough can be rolled the day before baking.

The recipe and be halved and baked in a 1/4 sheet pan. A 1/4 sheet slab pie will serve about 12 portions.

Did you make this recipe?

Please leave a comment on the blog or share a photo on Instagram

a slice of rhubarb pie on a plate

Perfect Pie Crust

Yield: 2 crust pie
Prep Time: 10 minutes
Chilling Time: 2 hours
Total Time: 2 hours 10 minutes

A Perfect Pie Crust is a thing of beauty. Because there are so few ingredients in a basic pie dough, how you mix those ingredients is crucial to achieve just the right texture. Add the fats in two stages to get a tender and flaky pie crust.


  • 2 cups (10 oz, 285g) all purpose flour (see note)
  • 2/3 cup (3.5 oz, 100g) cake flour
  • 1 teaspoon salt
  • 1 tablespoon granulated sugar
  • 1/2 cup (4 oz, 115g) leaf lard (or vegetable shortening), cold
  • 1/2 cup (4 oz, 115g) butter, very cold and sliced into 1/4" thin slices
  • 1/2 cup (4 oz, 118 ml) ice cold water


  1. Combine the all purpose and cake flour with the salt and sugar. Whisk together to mix the ingredients evenly.
  2. Using your fingers, cut the lard or shortening into the flour mixture until it resembles coarse corn meal. Using your fingers, toss the butter into the flour mixture. Allow the slices of butter to break up into slightly smaller pieces into the flour. Work quickly so the butter doesn't get warm. Don't break the butter down completely. There should be some large flakes remaining.
  3. Pour the water onto the flour all at once and toss to combine. Gently press the dough just until it comes together. It will look a little dry in spots. The water will redistribute in the dough as it rests.
  4. Wrap the dough and refrigerate for at least 2-3 hours before using.


This recipe uses a mixture of all purpose and cake flour to mimic pastry flour. All purpose flour will give the dough enough structure so it can hold the flaky texture and a small proportion of cake flour will help keep it tender. If you have pastry flour you can use that in place of the flour mixture.

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Did you make this recipe?

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Wednesday 3rd of March 2021

If using frozen berries do you thaw and drain them first? Thanks

Eileen Gray

Wednesday 3rd of March 2021

I would not. They'll probably give off a lot of juice as they thaw. I would toss the frozen berries with the sugar and other ingredients and fill the pie. You can skip the step to chill the pie since the frozen berries will keep the crust firm.

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