Confetti Cake Mix Berry Crumble Bars

These Confetti Cake Mix Berry Crumble Bars are the easiest way to turn a cake mix into a bakery-style bar cookie—without making cookies. You press a buttery confetti “shortbread” base into the pan, spoon in a berry layer, then sprinkle the remaining dough on top like a crumble. The result is a soft, sprinkle-studded crust with a bright fruit center and golden, crunchy topping. 

Yield

12 bars (8×8 pan)

Total Time

50 minutes

• 10 minutes prep
• 30–35 minutes bake
• 5–10 minutes cool (plus more if you want super clean slices)

Supplies Needed

• 8×8 baking pan
• Parchment paper (recommended for easy lift-out)
• Mixing bowl
• Fork or pastry cutter (for blending the crumble)
• Measuring cups/spoons
• Spatula
• Knife for slicing

Ingredients

Base + Crumble

• 1 box Benevolent Bakery Confetti Cake Mix
• 1/2 cup unsalted butter, melted
• 1 large egg
• 1/2 cup quick oats (optional, for a crunchier crumble)
• Pinch of salt

Berry Layer

• 3/4 cup berry jam (strawberry, raspberry, mixed berry, or cherry)
• 1 tsp lemon juice (optional, brightens flavor)
• 1 tbsp cornstarch (optional, helps the jam set thicker)

Optional Finish

• Powdered sugar for dusting
• White chocolate drizzle

Step-by-Step Instructions

1. Preheat + line the pan. Preheat oven to 350°F. Line an 8×8 pan with parchment paper, leaving an overhang for easy lifting.
2. Make the crumble mixture. In a bowl, combine the confetti cake mix, melted butter, egg, pinch of salt, and quick oats (if using). Mix with a fork until you get a thick, crumbly dough. It should hold together when squeezed but still crumble easily.
3. Press the base. Set aside about 1 cup of the mixture for the topping. Press the remaining dough firmly into the bottom of the pan in an even layer.
4. Mix the berry layer. Stir jam with lemon juice. If you want a thicker, less runny center, whisk in cornstarch until smooth.
5. Add the filling. Spoon the jam over the crust and spread into an even layer, leaving a tiny border around the edges.
6. Top with crumble. Sprinkle the reserved crumble mixture evenly over the jam. Don’t pack it down—loose crumbs bake up crisp.
7. Bake. Bake 30–35 minutes, until the top is lightly golden and the jam is bubbling at the edges.
8. Cool + slice. Let cool at least 10 minutes in the pan. For the cleanest slices, cool 30–45 minutes (or chill briefly). Lift out using parchment and cut into 12 bars.
9. Finish. Optional: dust with powdered sugar or drizzle with melted white chocolate.

Tips & Variations

• Flavor swap: Try apricot jam, lemon curd, or blueberry preserves.
• Extra crunch: Add 2 tbsp chopped nuts to the crumble topping.
• Storage: Keep airtight at room temp for 2 days or refrigerate up to 5 days. Great served chilled or room temp.