Start by preheating your oven to 350°F (175°C). This will ensure that your brownies bake evenly. In my experience, preheating is the key to achieving that perfectly set brownie texture.

Grab a 9x13-inch baking dish and grease it lightly. This prevents the brownies from sticking. Alternatively, you can line it with parchment paper for easy removal once baked. The last thing you want is a brownie mishap!

In a large mixing bowl, beat the softened cream cheese until smooth. Add in half of the confectioners' sugar (2 cups) and one of the separated eggs. Mix until it’s well combined. You want it creamy but without any lumps. Set this aside as we prepare the brownie batter.

In another bowl, combine the melted butter and the chocolate cake mix. Stir in the two remaining eggs, the vanilla extract, and a pinch of sea salt. Mix until the batter is smooth and glossy. This richness is what makes these brownies so unforgettable.

Pour half of the brownie batter into the prepared baking dish, smoothing it out to create an even layer. Then spread the cream cheese mixture over the brownie base. Finally, pour the remaining brownie batter on top. You can swirl a knife through the layers to create a marbled effect. Talk about an aesthetic treat!

Slide that beauty into the preheated oven and bake for around 30-35 minutes. You want to judge doneness by the edges pulling away from the sides. A toothpick inserted in the center should come out with a few moist crumbs—this ensures you’ve got that fudgy texture!

Once done, remove from the oven and allow it to cool in the pan. Patience is key here because warm brownies can be too gooey to slice. After they’ve cooled, cut them into squares and prepare for the applause you'll receive.