Preheat your oven to 350 degrees Fahrenheit. This is crucial for ensuring your blondies bake evenly. A well-preheated oven helps the edges crisp up while keeping the center delightfully gooey.
In a large mixing bowl, combine the first four ingredients: the yellow cake mix, canola or vegetable oil, and egg. Mix them together until well combined. You want a thick batter, so don't overmix it.
Gradually add the milk, starting with 1/4 cup. Mix thoroughly and check the consistency. You should aim for a thick batter; if it seems too dry, add a bit more milk but be careful not to make it too runny.
Once the batter is at the right consistency, gently fold in the sprinkles and white chocolate chips. It’s important to mix these in gently to maintain the airiness of the batter.
Prepare an 8 x 8 inch baking pan by greasing it or lining it with parchment paper. This will help prevent the blondies from sticking to the bottom.
Pour the batter into the prepared pan, spreading it evenly. Don’t forget to sprinkle a few extra sprinkles on top for a fun touch!
Bake in the preheated oven for 25 to 30 minutes. Keep an eye on them; you want the edges to turn a light golden brown while the center remains slightly gooey. A toothpick inserted into the center should come out with a few moist crumbs.
After baking, remove the blondies from the oven and let them cool in the pan for about 10 minutes. This cooling period allows them to set up a bit more.
Transfer the blondies to a wire rack to cool completely. This step is crucial for achieving that perfect chewy texture before you slice them.
Once they’re completely cooled, you can cut them into squares and serve. Enjoy the deliciousness of your homemade Cake Batter Blondies!