Preheat your oven to 350°F (175°C). This allows your cake to cook evenly and become beautifully golden brown.
Prepare a 9x13 inch baking dish by spraying it with non-stick cooking spray, ensuring easy release.
Spread the blueberries evenly in the bottom of the baking dish. You can use fresh or frozen blueberries, depending on what you have on hand.
Sprinkle the dry cake mix evenly over the blueberries, making sure every bit is covered.
Drizzle the melted butter over the dry cake mix, being careful to cover as much surface area as possible. This will create a deliciously golden crust.
Pour the water evenly over the top. This step is crucial as it helps to create that ooey-gooey delight we all love.
Do not stir! Just leave it as is to create the perfect texture when it bakes.
Bake in the preheated oven for 40-45 minutes, or until the top is golden brown and the cake is bubbling.
Let it cool slightly before serving. It’s best enjoyed warm, with a scoop of vanilla ice cream on top!