Strawberry Rhubarb Slab Pie is a classic dessert that’s perfect for any occasion. Spring and summer are about fruit pies and at the very first moment my local farmer’s market has fresh rhubarb and strawberries I just have  to make this easy recipe for any family gathering. Slab Pie is an easy grab and go dessert that can be packed up for spring and summer picnics and cook outs!

In the past I have shared a classic Strawberry Rhubarb Pie, but that was before I discovered how to best thicken pie filling when using berries and that filling was too juicy for a slab pie.

Ingredients needed for Strawberry-Rhubarb Slab Pie:

• All Purpose Flour
• ​Salt
• Sugar
• Butter
• Cold Water
• Strawberries
• Rhubarb
• White sugar (you can also use brown sugar!)
• Lemon Juice/lemon zest
• Tapioca Starch
• Supplies needed:

Supplies needed for Strawberry Rhubarb Slab Pie:

• Rolling pin
• Sheet pan/jelly roll pan
• Pastry cutter
• Large bowl

​The Process:

To make the crust, combine flour, salt and sugar in the bowl of a food processor. (You can also make by hand.)  Next, add unsalted butter, cut into small pieces, and process until butter is partially broken down. (With a pastry blender to work the butter into the flour mixture until it resembled coarse crumbs.) Then gradually add 1/4-1/2 cup ice water until the dough comes together in a ball. 

Divide the dough in half, flatten each half into a disc, and wrap them in plastic wrap before rolling out,  for at least 30 minutes.

For the filling, Mix sliced fresh rhubarb and sliced fresh strawberries in a large bowl. Toss with sugar, corn or tapioca starch, a pinch of salt and lemon juice. 

Preheat the oven to 375 degrees F. and roll out half of the dough on a lightly floured work surface until it is large enough to fit into a quarter sheet pan. Fit crust into the pan and trim pie crust edges. Then, pour in the fruit mixture into the crust, spreading it out evenly.

To make the top crust, you can either just roll out the second half of the crust, drape it over the fruit and cut slits in for steam, or you can cut into strips and make a lattice top like I did. Crimp edges and brush the top of the pie with a beaten egg wash and sprinkle with coarse sugar if desired. 

Bake for 45-50 minutes, or until the crust was golden brown and the filling was bubbly. Allow it to cool for at least 30 minutes before slicing and serving. Serve as is or with a scoop of ice cream if desired. 

Overall, this Strawberry Rhubarb Slab Pie is a perfect combination of sweet and tart flavors. It’s a great way to make good use of fresh rhubarb during rhubarb season in the spring. Plus, it’s an easy recipe that can be made with ingredients found at most grocery stores once rhubarb comes into season!

Strawberry Rhubarb Slab Pie is perfect for a picnic, cookout, or any event where you are looking for a utensil-free dessert that is full of spring-y flavors. (You can of course eat this with a fork, but the crust is sturdy and it’s totally snack-able.)

A note about pie thickener:

If you love berry pies as much as I do I strongly recommend getting your hands on some instant tapioca or tapioca starch (which is just instant tapioca ground to a powder.) Both work exceptionally well at absorbing excess liquid so your crust doesn’t end up a soggy mess. For this recipe I used enough to make sure the pieces were solid and not so juicy it was a mess to eat by picking it up, but for a juicier pie you could use less.  I buy this  from Amazon and it lasts me for a couple years of fruit pie baking. 

A note about the pan:

I like my quarter sheet pan for its high edges which keep the crust and filling nicely contained. This is the one I use!

Continue to Content

Strawberry Rhubarb Slab Pie

Yield: 12-15 servings

A beautiful spring pie baked in a sheet pan- perfect for packing up for a picnic!

Print

Ingredients

For the crust:

• 3 cups (390 g) all-purpose flour
• 1.5 tablespoon (22.5 g) granulated sugar
• 1 teaspoon fine sea or table salt
• 1.5 cups (390 grams, 12 ounces, 3 sticks or 24 tablespoons) cold, unsalted butter
• 3/4 cup (180 grams) very cold water

For the filling:

• 4 cups diced rhubarb (about a lb.)
• 4 cups diced strawberries (about a lb.)
• 3/4 cup sugar* (200g)
• juice of 1 lemon
• 3 tablespoons instant tapioca*

For the top of the crust:

• 1 egg, beaten
• 1-2 tablespoon sugar for sprinkling (fine or coarse is fine)

Instructions

For the crust:

Place your flour, sugar, and salt in a large bowl and whisk to combine.

Cut your butter into 1/2 inch cubes and add them into the flour mixture.

Toss them around so that they’re coated and used your fingers to roughly smash each butter cube into flatter pieces. (Don't over mix it, just smash each piece flat and toss with flour.)

Pour the cold water over butter-flour mixture and knead until the dough forms a ball. (It may feel more sticky than normal but it's ok!)

Divide dough into two parts, and turn onto a well-floured work surface. Roll each section into a rectangle (I did about 8x11,) and then fold the rectangle into thirds, then then in half, and wrap in plastic wrap.

Chill in the fridge until firm — one to two hours. (I usually do a little freezer time here if I'm in a pinch.)

!For the filling:

In a large bowl, combine the strawberries, rhubarb, sugar, lemon juice, and tapioca. Toss to combine and set aside until the crust is ready.

!To assemble:

Preheat oven to 425F.

Roll out one half of the dough to an 11x15 rectangle and transfer it to your quarter sheet pan. Gently press the crust up the sides and along the bottom.

Spoon in the filling and spread to the edges.

For the top crust, either simply roll out the second sheet and seal the edges, or cut into strips for a lattice top.

Brush crust with the beaten egg and sprinkle with sugar.

Bake for about 45 minutes, or until the filling seems bubbly and juicy. If the crust is getting too dark, lay a piece of tin foil over the top of the pie while the filling finishes cooking.

Allow to cool before slicing.

Notes

*3/4 cup sugar in the filling yields a pie that is sweet but not too sweet at all. I really wanted the tart rhubarb to shine so this is perfect for me. With some ice cream on top it's a wonderful dessert, or by itself it's mild enough for breakfast. If you want a sweeter pie- you could up it to a full cup.

Crust recipe from Bravetart.

Did you make this recipe?

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

Pin Strawberry Rhubarb Slab Pie for later!