Pre-heat oven to 325 degrees F. Grease & flour a 9" X 13" GLASS baking dish.
Prepare box cake mix as directed on package and pour into prepared baking dish...set aside DO NOT bake yet.
Mix together ricotta cheese, eggs, sugar, vanilla,and milk. Beating with electric mixer for 3 minutes until well blended.
Pour ricotta mixture gently and evenly over wet cake batter. Bake 1 hour and 15 minutes. When cake is done, the ricotta cheese should be a nice layer on the bottom of the baking dish with a wonderful moist sponge like cake layer on top. Don't worry if the ricotta cheese layer doesn't make it to the bottom of the cake dish....it's just as good if the ricotta layer ends up in the middle of the cake, too.
When cake is cool...sprinkle with powdered sugar or use fresh fruit in season, canned pie filling or use your imagination!