Base: Mix base cake and butter. Divide crumb mixture onto bottom of each of sixteen 3-inch springform pans. Bake in 300°F-conventional oven 6 min. Cool.
Filling: Place cream cheese, sugar and flour in large mixer bowl fitted with paddle attachment. Beat on low speed 2 min., stopping frequently to scrape side of bowl. Beat on medium speed 3 min. or until well blended. Add eggs, one at a time, mixing on low speed after each addition just until blended. Add sour cream; beat 1 min. Fold in OREO Pieces. Pour about 1 cup batter over each crust.
Bake in 300ºF-conventional oven for 35 to 40 min. or until centers are almost set. Run knife or metal spatula around rims of pans to loosen cakes; cool before removing rims of pans. Refrigerate 4 hours or overnight.