Triple Berry Crumb Bars with Brown Butter & Oats
These mixed berry crumb bars are layered with the juiciest mix of raspberries, blueberries, and blackberries that are perfectly jammy and not too sweet. The brown sugar oat crumb, made with nutty brown butter and rolled oats, bakes up soft in the center with irresistibly crisp edges. They taste like triple berry pie meets a cobbler in bar form, only way easier to make. Perfect for spring and summer baking, especially when you’ve got a bag of frozen berries to use up!
Equipment
Ingredients
Triple Berry Jam
- 1 cup frozen blackberries
- 1 cup frozen blueberries
- 1/2 cup frozen raspberries
- 2 tablespoons brown sugar packed
- 2 tablespoons granulated sugar
- 1 teaspoon lemon juice
- 1 tablespoon cornstarch
- 1 tablespoon water
Brown Butter Oat Crumble Crust
- 14 tablespoons unsalted butter
- 1/2 cup granulated sugar
- 1/2 cup brown sugar
- 2 teaspoons vanilla bean paste or extract
- 1 2/3 cup + 1 tablespoon all-purpose flour *See notes below for measuring*
- 1 cup old fashioned oats
- 1/2 teaspoon fine sea salt
Instructions
- Combine the berries, brown sugar, granulated sugar, and lemon juice in a pot. Cook over medium heat for 15-20 minutes, stirring and mashing occasionally, until the berries have released all of their juices, are bubbling, and starting to thicken. Try not to mash them too much, so you get chunks of jam! Stir in the cornstarch slurry and cook 2-3 minutes longer until thickened. Set aside to cool until ready to use.
- Line a square 8x8 baking pan with parchment paper to cover all four sides. Preheat the oven to 350°F/180°C.
- In a stainless steel pan, cook the butter over medium heat, stirring occasionally, until the butter is amber in color and the bottom of the pan is covered in brown milk solid bits. Scrape all of the butter into a large bowl and set aside to cool to room temperature.
- Once at room temp, whisk in the sugars and vanilla. Then mix in the flour, oats, and salt. Reserve roughly 1 cup (130 g) of the dough for the top, then press the rest of it firmly into the lined baking pan.
- Spread the berry filling across the dough, then break up the reserved dough into crumbles and spread it evenly on top of the berries. Bake for 35-40 minutes, or until the edges are bubbling and the crumble topping is golden brown. Let the bars cool for 3-4 hours before slicing into 16 squares. Enjoy!
Notes
*Measure your dry ingredients properly. This is my #1 baking tip! Do not ever scoop a measuring cup into your flour, as this always leads to using too much flour. Instead, use the spoon-level method. This means fluffing the flour first, then spooning it into your measuring cup/spoon. For the BEST results, use a kitchen scale!*
Storage: Leftovers can be stored in an airtight container at room temperature for 2-3 days.
Freezing: Freeze any bars in an airtight container or freezer bag for up to one month. Let the bars defrost at room temperature when ready to serve!
