Rhubarb Slab Pie

5 from 1 vote

This Rhubarb Slab Pie has a sweet and tart rhubarb and pear filling and a perfectly flaky all-butter crust. It’s a great way to use up fresh rhubarb this spring and this whole recipe comes together pretty easily once you have the crust already made. Serve as dessert with Smash Burgers and this Sweet Tea!

Prep Time1 5

Cook Time50

Chilling Time1 30

Total Time3 25

Course: Dessert, Pie

Cuisine: American

Diet: Vegetarian

Servings: servings or 1 (9x13-inch) slab pie

Author: Adrianna Adarme

Cost: $15

Equipment

1 box grater
1 Large mixing bowl
1 Medium-mixing bowl
1 Rolling Pin
1 9x13 inch Quarter baking sheet

Ingredients

Pie Crust:

4 cups 500g all-purpose flour
2 tablespoons 30g white granulated sugar
2 teaspoons fine-grain sea salt
1 1/2 cup 339g unsalted butter
1 cup very cold water divided

Filling:

1 pound rhubarb cut into 1/4-inch pieces
2 pears cored and cut into 1/4-inch slices
2/3 cup light brown sugar
2 tablespoons corn starch
Zest from 1 lemon or Meyer lemon
2 teaspoons vanilla extract
Pinch of salt

Toppings:

1 large egg + 2 tablespoons milk whisked together in a small bowl for egg wash
1 tablespoon turbinado sugar or demarrara
Ice cream or whipped cream for serving

Instructions

For the Pie Crust

In a large bowl, mix together the flour, sugar and salt. Using a box grater, grate the cold butter atop the flour mixture. Working quickly, and using your hands, break the butter bits into the flour until they’re evenly distributed and resemble the size of small peas.
Add 3/4 cup of water and mix. The mixture will be shaggy at this point. From here, add 1 tablespoon of water at a time until the dough comes together (I usually need to add 3 to 4 tablespoons). Flour your counter and dump the dough onto it. Knead a few times more until it comes together. Divide the dough by setting aside 1/3 of the dough (eye ball this measurement; this will act as the bottom of the pie, you want more for the top). Forming two discs, one smaller than the other. Wrap the discs in plastic wrap and transfer to the refrigerator to chill for at least 1 hour, ideally overnight.
Remove the first disc of dough from the refrigerator and allow to come to room temperature for 10 minutes. Liberally flour your work surface and rolling pin. Begin to roll the dough, being sure to rotate it every so often to avoid sticking, to a 13x10inch rectangle. Use your quarter baking sheet as a guide. Wrap the dough around the rolling pin and unroll it over the baking sheet. Gently fit the dough into the bottom and up the sides. Trim the dough around the pie tin, leaving a 1-inch overhang. Add your filling and transfer the pie to freezer while you roll out the second disc of dough.
Remove the second disc of dough from the refrigerator and repeat the rolling process as you did with the first disc. You have a couple of options, I chose to do an intricate thick lattice meets braided situation. For this, I rolled about a quarter of the dough into 7×9 inch rectangle. I sliced that into thick strips and placed them atop the pie. I transferred it to the fridge while I worked on the braids.

To Make the Braids

I rolled the dough into a big rectangle and sliced thin strips with a sharp knife. I took three of the strips and braided away. I continued this process until I was stressed and got through the dough. I then latticed the big strips with the thin braids. My biggest advice is that the freezer is your friend. If the dough ever gets too soft, transfer it to the fridge on a cutting board. Tuck the edges under or over and then crimp the edge all the way around the slab pie. Put it in the freezer to chill for 30 minutes. This will eliminate the possibility of shrinkage. Preheat the oven (see below for more instructions) and brush the entire thing with egg wash and sprinkle with turbinado sugar.

For the Rhubarb Pie

In a medium bowl, mix together the rhubarb, pear, brown sugar, corn starch, lemon zest, vanilla extract and salt. Allow to stand, about 10 to 15 minutes, while you assemble the pie crust.
Pour the filling into the slab pie crust (see above for assembling instructions). Roll the second half of dough and make any sort of design that you like. I chose a few wide strips of pie dough, weaved with a few strands of braided pie dough. Get as fancy as simple as you like. Tuck the edges under and crimp around the entire slab pie. Transfer to the freezer to chill for 30 minutes. Meanwhile, preheat the oven to 400 degrees F. Brush the top of the pie with a generous amoutn of egg wash and sprinkle with about a teaspoon of turbinado sugar.

Bake the pie

Place the slab pie on a half baking sheet and transfer to the oven to bake for about 20 minutes, until the crust is lightly golden brown. Turn the oven's heat down to 350 degrees F and bake for an additional 20 to 30 minutes, until the crust is golden brown and the filling is bubbling. Transfer to a cooling rack and allow to cool to room temperature, about 3 hours. If you cut into it before cooling it down, the filling will spill out, but is that the worst thing in the world? Nah. Serve with ice cream or whipped cream.

Notes

Tips and Tricks

The freezer is your friend. If the dough is ever feeling too soft while you are working with it, pop it back in the freezer for 30 minutes so it can firm back up. Also make sure to freeze the whole pie for 30 minutes before baking to eliminate the possibility of shrinkage in the oven.
Allow the pie to cool before serving. It’s best to wait at least 3 hours before trying to slice the pie otherwise the filling will spill out and make the bottom crust soggy.
Make this pie ahead of time. I love to make the pie crust the day before because it’s not only quicker to assemble day of but the extra time allows the gluten in the flour to relax = flakier crust without shrinkage.
Pie Crust 101 Guide. If you need any help with making this pie crust check out my Homemade Pie Crust Guide, it goes over everything you need know!

Nutrition