Blueberry Slab Pie (aka Blueberry Pie Bars)

The ultimate summer party pie! Blueberry slab pie (also known as blueberry pie bars) is the large-scale version of the best blueberry pie you’ve ever had! A great option for summer potlucks, backyard barbeques, and pool parties.

It was difficult to put into words just how good this blueberry slab pie is. This summer pie is just next-level delicious. Blueberries bursting with sweet goodness, flakey and buttery crust, and the perfect crumble topping. Oh, and did I mention there’s a splash of booze in it? Yeah, there’s some hooch in this slab pie recipe, and it’ll leave you wondering why you haven’t liquored-up every pie you’ve ever made before.

Let’s review all the boxes this beauty checks: fabulous blueberry dessert? Check. One of the best desserts for crowds? Check (spoiler alert, this pie is massive). Something your friends have never seen before? Check. One of your new favorite desserts for the summer? Check.

If you’ve been looking for new party desserts to make, give this blueberry slab pie recipe a try for your next gathering!

Key Ingredients for this Recipe

Buttery Pie Crust: A good pie crust creates the perfect base for any pie. This slab pie uses an all butter crust recipe, and is an absolute joy! Light and flaky perfection.

Blueberries: Surprising no one, the star of this blueberry dessert is blueberries. This is the perfect summer pie because blueberries are in peak-season in July and August. I know this because during this time, my husband comes home with at least four pints of blueberries after every grocery store run, even if he just went for milk…fridge space is hard to come by in the summertime! This blueberry pie filling is packed with 3 whole pints of blueberries! YUM.

Orange (juice, zest, liqueur): The fresh orange juice and zest, along with the warmth of the orange liqueur, take this pie from a good summer pie to one that people will rave about. In the dead of winter, when blueberry season is far away, your friends will reminisce about this pie and count down the days until you can make it again.

Old Fashioned Oats: Old fashioned oats add a wonderfully chewy texture to the crumble topping of this pie. I do NOT recommend using quick-cook oats for your topping, they are too delicate and will not create a nice texture.

Full ingredient list and all ingredient measurements can be found in the recipe card at the bottom of the page.

How to Make Blueberry Pie Bars with Oatmeal Crumble

Prepare the crust dough: I recommend prepping your crust in a food processor because it’s fast and easy! You can also use a pastry cutter, fork, or your hands. Once you have prepared your dough, make sure to chill it for at least 2 hours before rolling it out to allow the butter to re-harden. This will give you that flakey crust you are hoping for!

Prepare blueberry filling: While the crust is nearing the end of it’s chill time, place blueberries, orange zest, orange juice, and orange liqueur in a medium sized mixing bowl and toss to coat. Add sugar, flour, and cinnamon to the bowl and toss to coat. Set aside until ready to fill the crust.

Prepare crumble topping: After putting together your blueberry pie filling, add oatmeal, brown sugar, and flour into a medium bowl and mix to combine. Add softened butter and cut in with a fork or pastry cutter until large clumps form. Set aside until you’re ready to assemble your pie.

Roll out pie crust and prepare your pan: When ready to use, place chilled dough onto a floured surface and gently roll out with a floured rolling pin. Start from the center of the dough and work towards the edges. Roll dough onto a rolling pin and transfer to a jelly roll pan. Push into corners. Remove excess dough that folds over the top edge of the pan (you can do this easily by rolling your rolling pin along the edges, this will basically ‘cut’ the dough at the very top edge of your pan).

Assemble your pie: Pour blueberry pie filling into prepared crust and spread into an even layer. Sprinkle crumble topping evenly over the top of your filling. Crimp edges of pie crust with your fingers.

Bake: Preheat the oven to 400°F while preparing your filling and topping. When ready to bake, drop heat to 375°F. Bake for 45-55 minutes until bubbly and crust is lightly browned.

Cool and serve: Cool slightly before serving! Serving with vanilla ice cream is optional, but highly recommended!

Store: Fruit pies can be stored at room temperature for up to 2-days, or in the fridge for up to 4-days. I personally like to store my leftover slab pie in the fridge, and heat up slices when we want to enjoy them.

Time Saving Tips

Option 1: Make Your Pie Crust Ahead of Time

You can pre-make your pie crust dough to save time on the day you’d like to bake your pie!

Your dough needs to chill at least 2 hours before rolling out, but it can chill in your fridge for up to 5 days. You can also freeze pie crust dough for up to 3 months. If you choose to freeze your pie crust dough, place the flattened / wrapped rectangle of dough in Step 5 of the ‘Prepare Your Crust’ section. Thaw overnight in the fridge prior to using for your slab pie.

Option 2: Use Store-Bought Pie Crust

If you don’t want to make your own crust, or want to save time, you can buy pie crust in the frozen section of your local grocery store!

The all butter pie crust recipe used for this slab pie is a ‘double crust’ (aka enough to make 2 pies, or one pie with a top crust). So if you’re going to purchase store-bought pastry, make sure it’s enough for two pies. Then roll out and prepare your crust per the recipe, starting at Step 6 of the ‘Prepare Your Crust’ section.

Blueberry Slab Pie FAQs

Do I need to add the crumble right away? Won’t it burn? Nope! Go ahead and add that delicious crumble right away. There will be enough moisture leaving the blueberries to keep the crumble from getting scorched, so just let all those delicious ingredients do their thing!

Should I use fresh or frozen blueberries? This recipe was written with fresh blueberries in mind. However, you can definitely swap out for frozen blueberries (they work great for baking!). Make sure you thaw your blueberries prior to using. You can do this by soaking them in a bowl of warm water for 5-10 minutes. If they’re still frozen, replace the water with fresh warm water. You can also defrost your frozen berries in the microwave on the defrost setting for approximately 30 seconds.

Where I’m from, highbush blueberries (the small, more wild-looking variety) aren’t common to find fresh, but we can get them frozen. Highbush blueberries are very, very good, and would certainly be a welcome addition to any pie!