In a large bowl, heat the jelly in the microwave on high in 30-second increments, stirring occasionally, until just melted but not hot. Whisk the jelly until smooth. (If it's hot, let cool before continuing.)
Add 1 cup whipped topping to the jelly; whisk until smooth. Add the remaining whipped topping; gently fold until just blended.
Spread 2 tbsp. grape cream in the bottom of a 9-inch pie or tart pan. Arrange about 18 crackers on the cream in an even layer (do not overlap). Top with 1 cup grape cream. (As you build the cake, be sure to leave some of the edges of the crackers exposed.) Arrange about 12 crackers on top of the cream in an even layer; top with 1 cup cream. Arrange about 7 crackers on top of the cream; top with 1 cup cream. Repeat with 7 more crackers and top with 1/2 cup cream. Arrange about 6 crackers on top of the cream; top with 1/2 cup cream. Arrange about 3 crackers on top of the cream; top with remaining cream. Top with 1 cracker.
Refrigerate the cake until the crackers soften, at least 4 hours but preferably overnight.