BLUEBERRY-APPLE CRUMBLE BARS

Minnesota is known for its potluck culture, and I’ve made plenty of bars over the years to share at get-togethers, church picnics, and funerals. These are my go-to bars on most occasions; the shortbread crust, blueberry-apple filling, and streusel top are always a hit. This recipe can be doubled and baked in a half sheet pan, making it perfect for larger gatherings. makes 12 large or 24 small bars

CRUST

2½ cups (355 g) all-purpose flour

½ cup (45 g) rolled or quick oats

1 cup (198 g) sugar

1 teaspoon baking powder

½ teaspoon salt

½ teaspoon cinnamon

½ pound (2 sticks; 227 g) unsalted butter, at room temperature, and sliced into 1-inch pieces

BLUEBERRY FILLING

5 heaping cups blueberries (700 g)

½ cup (75 g) grated Gala apple (about one small apple)

1 tablespoon lemon juice

⅓ cup (66 g) sugar

2 tablespoons cornstarch

Pinch salt

Adjust an oven rack to the middle position. Preheat the oven to 350°F. Grease a 9 by 13-inch baking pan and line it with a parchment sling.

In the bowl of a stand mixer fitted with a paddle, mix the flour, oats, sugars, baking soda, salt, and cinnamon on low to combine. Add the butter and mix on medium until mixture resembles coarse sand.

Press half the flour-oat mixture into the bottom of the prepared pan. Bake 10 minutes. Prepare the berry filling while the crust is baking (see below). Remove the pan from the oven, spread the berry mixture over the crust, and sprinkle the remaining crumble mixture evenly over the top. Bake 20 to 25 minutes, until the crumbly top is light golden brown.

Transfer to a wire rack and let cool. Place the pan in the fridge and let chill 4 to 6 hours. Slice bars and serve. The bars can be served cold or at room temperature, but keep best in the fridge.

FOR THE BERRY FILLING: In a large bowl, mix the berries, apple, and lemon juice.

In a small bowl, combine the sugar, cornstarch, cinnamon, and salt. Pour the sugar mixture over the berries and stir gently with a spatula to evenly combine.