| | CRUST |
| 27 | | Original Oreos; finely crushed |
| | ; (including filling) |
| 5 | tb | Butter; melted |
| | CAKE |
| 16 | | Original Oreo cookies; coarsely crushed |
| | ; (including filling) |
| 2 1/4 | c | Flour |
| 1 1/2 | ts | Each: baking powder and baking soda |
| 1/2 | c | Butter |
| 1 1/3 | c | Sugar |
| 3 | | Eggs; separated |
| 2/3 | c | Sour cream |
| 2 1/2 | oz | Semisweet chocolate; melted |
| 1/2 | ts | Vanilla extract |
| 1 1/3 | c | Water |
| | FILLING |
| 5 | ts | Softened butter |
| 2 1/2 | c | Sifted confectioners' sugar |
| 3/4 | ts | Vanilla extract |
| 1/4 | c | Milk; (approximately) |
| | FROSTING |
| 5 | tb | Softened butter |
| 2 1/3 | c | Sifted confectioners' sugar |
| 1/4 | | Dark cocoa |
| 1/2 | ts | Vanilla extract |
| 1/4 | c | Milk or heavy cream; (approximately) |
| | GARNISH |
| | Additional crushed original Oreos |
| | Miniature Oreos or original Oreos cut |
| | ; into fourths |
