Generously spray a 9 x 13 baking pan with cooking spray
Melt butter on the stovetop using a heavy saucepan. You can melt it in the microwave as well, but I feel I have more control on the stovetop.
Remove from heat and stir in softened cream cheese until it mostly melts.
Stir in white chocolate chips. Chips don’t have to melt completely. Set aside.
Put cake mix in a mixing bowl. Add eggs, oil, and sour cream. Mix until smooth.
Spread cake batter evenly in oiled baking pan.
Drop dollops of the cream cheese mixture over the cake batter. Make sure you get some around the edges.
Sprinkle chocolate chips over all.
Bake for 50 minutes. Don’t over cook it, remove from oven after 50 minutes. If you test the center with a toothpick the toothpick will not come out clean, you might think the cake is not done, but it is, the center is supposed to be gooey.
Serve warm or cold, it’s delicious either way. My son loves it with a scoop of vanilla ice cream!