Preheat the oven to 350°F. Spray a 9×13-inch baking dish with cooking spray (I like the kind with flour in it) and set aside.
In a microwave-safe bowl, melt ½ cup (1 stick) salted butter and allow to cool slightly.
In a large bowl fitted with an electric hand mixer or in the bowl of a stand mixer fitted with the paddle attachment, mix together 15.25 ounce box red velvet cake mix, melted butter (from the previous step), 2 eggs, and ½ Tablespoon vanilla extract until well combined. The mixture will be thick.
Press this mixture until the bottom of the 9×13-inch baking dish.NOTE: You might find it helpful to spray your clean hands with a little of the nonstick cooking spray to help press it in.
Melt the remaining ¼ cup (½ stick) salted butter and allow to cool slightly.
In a medium bowl with an electric hand mixer or in the body of a stand mixer with the paddle attachment, whip together 8 ounce block cream cheese, softened to room temperature, melted butter (from the previous step), remaining 1/2 Tablespoon vanilla extract, and remaining 2 eggs until smooth.
Add 5 cups powdered sugar and slowly stir to combine.
Pour this mixture over the crust.
Cover with foil.
Bake on the middle oven rack for 30 minutes, uncover and bake an additional 15-20 minutes until slightly golden brown with a thin, crisp crust on top. It will have a dip in the middle; this is normal. Don't cook for too long, or you will lose the gooeyness in the center.
Allow to cool before slicing to serve. I like to run a butter knife along the entire edge of the baking dish to make sure it doesn’t stick.
Allow to cool then dust the top with a little more powdered sugar.
Notes
Please refer to my FAQ’s (Frequently Asked Questions) and ingredient list above for other substitutions or for the answers to the most common questions.
I suggest sticking to the 15.25 ounce boxes of cake mix if you can. I find they work better than the smaller cake mixes.