Halloween Oreo Cake Bars
Halloween Oreo cake bars are thick, soft vanilla bars with coarse cookie pieces underneath and across the top. Orange-and-black sprinkles add the Halloween color without frosting. The cut bars are cakey and moist, not crisp like cookie bars.
The cake-mix batter is deliberately stiff. Dolloping it across the pan before spreading helps keep the bottom Oreo layer in place, and pressing the top pieces lightly into the batter helps them stay attached after baking. You’ll need one bowl and a 9-inch-square pan.
Ingredients for Halloween Oreo Cake Bars
- 1 standard box vanilla or French vanilla cake mix, about 15.25 ounces (430g)
- 2 large eggs
- 1/2 cup whole milk (120g)
- 1/3 cup canola or vegetable oil (70g)
- 18 Halloween Oreo cookies, coarsely chopped (about 200g), divided
- 2 tablespoons orange-and-black Halloween sprinkles (about 20g), divided
- Nonstick cooking spray, as needed
Leave the Oreos in uneven, recognizable pieces rather than crushing them into crumbs. Regular Oreos also work; the sprinkles will provide the Halloween color.
How to Bake Halloween Oreo Cake Bars
- Prepare the pan: Preheat the oven to 350°F (175°C). Line a 9-inch-square metal baking pan with two crossing strips of parchment, leaving at least 2 inches of overhang on two opposite sides. Lightly spray any exposed pan areas.
- Layer the Oreos: Scatter about half of the chopped Oreos evenly over the bottom of the pan. Reserve the rest for the top.
- Mix the batter: In a large bowl, mix the cake mix, eggs, milk, oil, and 1 tablespoon of the sprinkles until no dry streaks remain. The batter will be thick; do not add extra milk to thin it.
- Spread and decorate: Dollop the batter in several spots over the Oreos. Lightly spray an offset or silicone spatula, then gently press and spread the batter to the corners without dragging the bottom cookies out of place. Scatter the reserved Oreos and remaining sprinkles over the surface. Press the Oreo pieces in lightly, leaving them partly exposed.
- Bake: Bake uncovered for 20 to 25 minutes, beginning to check at 20 minutes. The edges should be lightly golden and the center set, not wet or glossy. A toothpick inserted into a cake-only area near the center should come out clean or with a few moist crumbs, not wet batter.
- Cool and cut: Cool completely in the pan, about 45 to 60 minutes. Lift out the slab by the parchment overhang and cut into 12 small squares or rectangles. Wipe the knife between cuts for neater edges.
How to Tell When the Bars Are Done
The 20-to-25-minute range applies to this one-box batch in a 9-inch-square metal pan; it does not carry over to a doubled batch in a 9-by-13-inch pan. Test through the cake rather than an Oreo pocket, which can make the toothpick result misleading. A few moist crumbs are fine, but a glossy center or wet batter needs more time.
If using a glass or ceramic pan, begin checking at 22 minutes and use the same doneness cues rather than relying on the clock alone.
Serving and Variations
Serve the cooled bars plain as a hand-held dessert, or add vanilla ice cream alongside a bar for a plated serving. For an Oreo-themed dessert table, add No-Bake Witch Hat Oreos.
Halloween funfetti cake mix can replace the vanilla mix. If it already contains plenty of sprinkles, reduce or omit the added sprinkles, but keep the coarse Oreo topping.
Storage and Make-Ahead
Store fully cooled bars in an airtight container at room temperature for up to 1 week. Their soft texture and topping look best within about 3 days. Place parchment between layers if stacking. To make them up to 24 hours ahead, let them cool completely before covering.
For longer storage, freeze cooled bars in a freezer-safe bag or airtight container for up to 3 months, with parchment between layers. Thaw overnight in the refrigerator, then serve at room temperature. Reheating is unnecessary.
Nutrition
Approximate nutrition per bar, based on 12 bars: 295 calories, 4g protein, 12g fat, and 44g carbohydrates. Approximate values per 100g of finished bars: 390 calories, 5g protein, 16g fat, and 59g carbohydrates. Values will vary with the cake mix, cookies, sprinkles, and final baked weight.
Equipment
- 9-inch square metal baking pan
- parchment paper
- large mixing bowl
- offset or silicone spatula
- toothpick
Ingredients
For the Cake Bars
- 1 standard box vanilla or French vanilla cake mix, about 15.25 ounces (430 g)
- 2 large eggs
- 1/2 cup whole milk (120 g)
- 1/3 cup canola or vegetable oil (70 g)
- 18 Halloween Oreo cookies, coarsely chopped (about 200 g), divided
- 2 tablespoons orange-and-black Halloween sprinkles (about 20 g), divided
- Nonstick cooking spray, as needed
Instructions
- Preheat the oven to 350°F (175°C).
- Line a 9-inch-square metal baking pan with two crossing strips of parchment paper, leaving at least 2 inches of overhang on opposite sides. Lightly spray exposed pan areas with nonstick cooking spray.
- Scatter half of the chopped Oreos evenly over the bottom of the prepared pan.
- Mix the cake mix, eggs, milk, oil, and 1 tablespoon of sprinkles in a large bowl until no dry streaks remain. Keep the batter thick; do not add extra milk.
- Dollop the batter over the Oreo layer. Lightly spray an offset or silicone spatula, then gently spread the batter to the corners without moving the bottom cookie pieces.
- Scatter the remaining chopped Oreos and sprinkles over the batter. Lightly press the Oreo pieces into the surface, leaving them partly exposed.
- Bake uncovered for 20 to 25 minutes, checking at 20 minutes. The edges should be lightly golden and the center should be set.
- Test a cake-only area near the center with a toothpick; it should come out clean or with a few moist crumbs, not wet batter.
- Cool completely in the pan for 45 to 60 minutes.
- Lift out the slab using the parchment overhang and cut into 12 squares or rectangles, wiping the knife between cuts.
Tips
- Keep the Oreos in coarse, uneven pieces instead of crushing them into crumbs.
- Dollop the thick batter over the bottom Oreo layer before spreading so the cookies stay in place.
- Lightly spray the spatula to make spreading the stiff batter easier.
- Check doneness in a cake-only area, not through an Oreo pocket.
- For glass or ceramic pans, begin checking at 22 minutes and use the visual doneness cues.
Variations
- Funfetti Halloween Bars: Use Halloween funfetti cake mix in place of vanilla cake mix; reduce or omit the added sprinkles if the mix already contains plenty.
- Regular Oreo Bars: Use regular Oreos instead of Halloween Oreos and keep the orange-and-black sprinkles for Halloween color.
