Preheat oven to 350 degrees and butter or spray a 9 x 13 pan.
Mix base ingredients well. Spread dough in bottom and 1/2 inch up the sides of the pan. Set aside.
For the filling: With an electric mixer, whip the cheese until creamy, beat in eggs and then the condensed milk and vanilla.
Spread the filling over the dough in pan. Bake for 35 minutes, no longer. (The filling should be turning golden brown.) Do not over bake.
The filling will thicken as it cools.
When completely cool, dust with powdered sugar, if desired.