Preheat oven to 350 °F (177 °C). Grease a 10″ bundt pan with nonstick spray.

In a large bowl, whisk together the cake mix, brownie mix, eggs, water, and oil until smooth and nearly lump‑free.

Pour batter into the prepared bundt pan. Bake for 50–55 minutes, or until a toothpick inserted comes out with a few moist crumbs.

Let cool in the pan for 10 minutes, then invert onto a wire rack and cool another 30 minutes.

For the ganache: heat heavy cream until simmering, then pour over chocolate chips in a heat‑proof bowl. Let sit 5 minutes, then whisk until glossy and smooth.

Pour ganache over the cooled cake, allowing it to drip down the sides. Slice and serve.