Gooey Butter Cake with Orange Liqueur

It was really just a matter of time until I got around to sharing a gooey butter cake recipe on the blog, as it is the unofficial dessert of St. Louis, where I make my home, and also a dessert that I've loved eating my whole life. There is nothing else quite like it. In the traditional recipe, the crust is made with a yeast dough, but that isn't the gooey butter cake most people have tried. Everyone I know uses the yellow cake mix shortcut, which is not only easier, some say its even tastier than the traditional version. One of these days I'm going to have to make the traditional recipe just so I know for sure which I prefer, but until I have more time on my hands, I'm sticking with the tried and true. I spiced things up a bit by adding a little Grand Marnier:  not enough that it tastes blatantly boozy, but just so it has a subtle hint of orange. You can substitute any orange liqueur if you don't have Grand Marnier.