CAKE-Blend cake mix, butter and eggs together well in medium mixing bowl until crumbly but moist. Pat mixture evenly over bottom of Pam sprayed jelly roll pan. Pat it lightly but evenly. Set aside while you preheat oven to 350~ and prepare the filling. FILLING-Combine cream cheese, sugar and vanilla well in 2-qt bowl, beating with mixer on medium speed until smooth. (About 5 minutes beating time). Pour over cake mix layer. Place on center rack of oven and bake at 350~, about 30 to 35 minutes or until golden brown and top looks like a nicely baked cheesecake would. Cool in pan on rack 1 hour. Cut into neat serving squares and refrigerate, covered in plastic wrap to serve within a few days. Does NOT freeze well.