Chocolate Cake: Spray bottoms and sides of 3 (10-inch) round cake pans with cooking spray. Line bottoms with parchment paper.
Beat sugar, oil and eggs with electric mixer fitted with whisk attachment on high speed until light yellow in color.
Mix flour, cocoa, baking powder and soda in bowl. Mix milk and coffee in separate bowl. Add dry ingredients to egg mixture alternately with liquid ingredients, beginning and ending with dry ingredients. Mix until combined after each addition, scraping side of bowl. Divide batter evenly among prepared pans. Sprinkle evenly with OREO Pieces.
Bake in 350°F standard oven 35 to 40 min. or until tops spring back when lightly touched. Cool completely in pans on wire racks. Remove cakes from pans; gently remove parchment.
Chocolate Filling: Bring cream, sugar, butter and water to boil on medium heat. Remove from heat and pour over chocolate in bowl. Let stand 1 min. Stir until mixture is smooth and shiny. Stir in liquor. Refrigerate, or let stand at room temperature several hours or until mixture is firm.
Cream Filling: Sprinkle gelatin over water in saucepan and allow to soften. Cook on low heat until gelatin is dissolved. Stir in liquor.
Whip cream with electric mixer fitted with whisk attachment on high speed until soft peaks form. Whisk in sugar. Add a large spoonful of the cream mixture to the gelatin mixture; whisk quickly until combined. Immediately add gelatin mixture to remaining cream in bowl. Whip on high speed until stiff peaks form.
Assembly: Place one cake layer on cake plate or cardboard circle. Top with half the Chocolate Filling, spreading evenly and carefully just to edge of cake. Top with second cake layer. Spread Cream Filling evenly and carefully over cake. Top with third cake layer and remaining Chocolate Filling. Spread to edge of cake. Refrigerate several hours or until filling is set.
Cut chilled cake into 16 slices. Serve at room temperature.