1-Prepare the baking dish: Ready to get your hands messy and create something amazing? Start by preheating your oven to 350°F and lining a 9×13-inch baking dish with parchment paper for easy removal later. This pistachio gooey butter cake comes together in a flash, with most of the work happening in one bowl to keep things straightforward.

2-Make the crust: In a large bowl, beat together the yellow cake mix (13.25 oz), melted salted butter (½ cup), and 1 large egg until everything is nicely combined, which usually takes about 2 minutes. Press this mixture into the bottom of your baking dish to form a solid crust that holds everything in place.

3-Prepare the filling: Using the same bowl to save on cleanup, beat the cream cheese (8 oz, at room temperature), 2 large eggs, vanilla extract (1 teaspoon), and melted salted butter (½ cup) until the mixture is super smooth. Gradually add the powdered sugar (3 cups), one cup at a time, and mix until it’s creamy and dreamy.

4-Assemble and bake: Pour this filling right over your crust, then spoon on the pistachio cream (¾ cup) in dollops and swirl it gently with a knife for that pretty pattern. Pop it in the oven and bake for 30-35 minutes, until the edges are set and golden while the center stays a bit jiggly. Let it cool until it’s firm enough to cut, then sprinkle on the flaky salt (½ teaspoon) for a finishing touch that adds a salty crunch.