Ingredients
- 1 box (15.25 oz) yellow cake mix (chocolate, funfetti, or other flavors also work)
- 2 large eggs
- 1/3 cup vegetable oil
- 1 cup dark chocolate chips
- 1 cup milk chocolate chips
- 1 cup white chocolate chips
Using cake mix, eggs, and oil mirrors many U.S. “cake mix cookie bar” and “lazy chocolate chip cookie bar” recipes, which rely on this trio for a soft, chewy texture.
Step-by-step instructions
Prep the pan
Preheat your oven to 350°F (175°C). Grease a 9×13‑inch baking dish with butter or non‑stick spray; lining it with parchment and greasing over the top makes lifting and slicing much easier, as recommended in similar cake mix bar recipes.
Mix the dough
In a large mixing bowl, combine the dry cake mix, eggs, and vegetable oil. Use an electric mixer or sturdy spatula to mix until the dough comes together; it will look crumbly at first and then turn into a very thick, sticky dough, which is exactly how cake mix cookie bar dough should look.
Fold in all three kinds of chocolate chips until they’re evenly distributed. Save a small handful if you want to press extra chips on top for that molten, bakery-style finish you see in gooey cookie bar recipes.
Press and bake
Transfer the thick dough into the prepared pan. Use a greased spatula, an offset spatula, or lightly oiled fingertips to press it firmly into an even layer, reaching all four corners; most cake mix bar recipes note that this step takes a minute because the dough is so thick.
Bake for 20–25 minutes, until:
- The top is lightly golden
- The edges are just starting to pull away from the sides
- The center still looks slightly soft but not raw
These visual cues match other cake mix cookie bar and blondie recipes that aim for soft, chewy centers instead of dry, cake‑like bars.
Cool and slice
Set the pan on a cooling rack and let the bars cool in the pan for at least 30 minutes before cutting. Cooling lets the structure set so you get clean squares instead of molten puddles, a tip repeated across cake mix bar recipes.
Use the parchment to lift the slab out, then cut into squares or rectangles with a sharp knife. For extra gooey bars, you can slightly underbake and enjoy them still a bit warm with a scoop of ice cream.
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