Preheat oven to 350°F (175°C). Grease a 9×13 inch baking dish.

Pour melted butter into the baking dish and sprinkle with brown sugar evenly.

Arrange sliced strawberries over the brown sugar.

In a large bowl, prepare the cake mix according to the package instructions, using water, vegetable oil, and eggs.

Pour the batter over the strawberries in the baking dish.

Bake for 40-45 minutes or until a toothpick inserted into the center comes out clean.

Allow the cake to cool in the dish for 5 minutes, then carefully invert onto a serving platter.

Let the cake cool completely before serving.