Peach Slab Pie Bars with Oat Crumble

Name: Peach Slab Pie Bars with Oat Crumble
Prep time: 30 min
Cook time: 50 min
Total time: 1 h 20 min
Yield: 24
Cuisine: American
Ingredients: 3 cups All-Purpose Flour; 3/4 cup Granulated Sugar; 1 teaspoon Kosher Salt; 1 1/2 cups Unsalted Butter, Cold and Cubed; 2 Large Egg Yolks; 3 tablespoons Ice Water; 4 pounds Ripe Peaches, Peeled and Sliced; 2/3 cup Granulated Sugar; 1/3 cup Cornstarch; 2 tablespoons Fresh Lemon Juice; 2 teaspoons Vanilla Extract; 1 teaspoon Ground Cinnamon; 1/4 teaspoon Ground Nutmeg; 1 1/2 cups Old-Fashioned Rolled Oats; 3/4 cup All-Purpose Flour; 3/4 cup Packed Light Brown Sugar; 1/2 teaspoon Kosher Salt; 1/2 cup Unsalted Butter, Melted

Peach slab pie bars with oat crumble on a platter

Doris Cook

Published: July 27, 2026

Categories: Pies, Fruits

Tags: Potluck, Summer Dessert, Fruit Dessert, Oat Crumble, Slab Pie, Peaches, National Night Out

Peach Slab Pie Bars

Buttery slab pie bars layered with juicy summer peaches and a crisp brown sugar oat crumble, baked in one large pan for easy potluck sharing.

Prep Time:30 minCook Time:50 minTotal Time:80 minServings:24Difficulty:Medium

A slab pie turns peak-season peaches into a dessert that is much easier to serve outdoors than individual slices of a deep pie. The broad pan gives every bar a balanced bite of buttery crust, tender fruit, and crisp oat topping.

The bottom crust is pressed directly into a rimmed sheet pan and briefly baked before filling. That head start keeps the base sturdy beneath the peach juices, so the cooled bars can be lifted, carried, and eaten without a plate when necessary.

Lemon juice sharpens the fruit, while cinnamon and nutmeg stay in the background. The oat crumble adds toasted texture and enough brown sugar richness to follow smoky barbecue without competing with a chocolate dessert elsewhere on the table.

Cool the slab completely before cutting; the peach filling thickens as it rests and will hold clean edges. For a block party, arrange the bars in a single layer on a covered tray and keep them out of direct sun until dessert.

Nutrition (per serving)

Calories:285 kcal

Protein:4 g

Carbs:39 g

Fat:14 g

Directions

1

Heat the oven to 375°F. Line a 13-by-18-inch rimmed baking sheet with parchment, leaving overhang on the two long sides, and lightly grease the exposed ends.
2

Pulse 3 cups flour, 3/4 cup granulated sugar, and 1 teaspoon salt in a food processor. Add the cold butter and pulse until the mixture forms coarse crumbs with pea-size pieces.
3

Add the egg yolks and ice water. Pulse just until the dough holds together when squeezed. Scatter it over the prepared pan, then press it into a firm, even layer across the bottom.
4

Bake the crust for 15 minutes, until the surface looks dry and the edges are just beginning to turn golden. Set the pan on a rack while you prepare the filling.
5

Gently toss the peaches with 2/3 cup granulated sugar, cornstarch, lemon juice, vanilla, cinnamon, and nutmeg until no dry patches remain. Spread the filling evenly over the warm crust.
6

Stir the oats, 3/4 cup flour, brown sugar, and 1/2 teaspoon salt in a bowl. Pour in the melted butter and mix with a fork until moist clumps form.
7

Scatter the oat crumble evenly over the peaches, breaking up any clumps larger than a walnut so the topping bakes uniformly.
8

Bake for 32 to 35 minutes, rotating the pan halfway through, until the filling bubbles across the center and the crumble is deep golden brown.
9

Cool completely in the pan on a rack for at least 2 hours. Lift out the slab with the parchment, trim the edges if desired, and cut into 24 bars with a sharp knife.

Ingredients

All-Purpose Flour:3 cups
Granulated Sugar:3/4 cup
Kosher Salt:1 teaspoon
Unsalted Butter, Cold and Cubed:1 1/2 cups
Large Egg Yolks:2
Ice Water:3 tablespoons
Ripe Peaches, Peeled and Sliced:4 pounds
Granulated Sugar:2/3 cup
Cornstarch:1/3 cup
Fresh Lemon Juice:2 tablespoons
Vanilla Extract:2 teaspoons
Ground Cinnamon:1 teaspoon
Ground Nutmeg:1/4 teaspoon
Old-Fashioned Rolled Oats:1 1/2 cups
All-Purpose Flour:3/4 cup
Packed Light Brown Sugar:3/4 cup
Kosher Salt:1/2 teaspoon
Unsalted Butter, Melted:1/2 cup

Tips & Notes

Choose fragrant peaches that yield slightly to pressure but are still firm enough to slice neatly.
If the peaches are exceptionally juicy, let the tossed filling stand for 5 minutes and leave excess liquid behind when spreading it over the crust.
Store the cooled bars in a single layer in an airtight container for up to 2 days at room temperature or 4 days refrigerated.