Aunt Connie's Chocolate Eclair Cake

16 oz. box honey graham crackers
2 - 3 and 3/4 oz. package instant French vanilla pudding mix
3 cups and 3 tablespoons milk
12 oz. carton Cool Whip - thawed
1 and 1/2 cup powdered sugar
6 tablespoons cocoa
2 tablespoons butter
2 teaspoons light corn syrup
1 teaspoon vanilla

Place a single layer of graham crackers in bottom of a 9 x 13 pan. Combine pudding mix with 3 cups milk. Stir until thickened. Fold in whipped topping. Spread 1/2 of pudding mixture on graham cracker layer. Add another layer of graham crackers. Cover with remaining pudding mixture. Top with a layer of crackers. In a small saucepan, combine powdered sugar, cocoa, butter, remaining milk, corn syrup, and vanilla. Stir over low heat until just liquified. Pour over top layer of crackers. Refrigerate at least 24 hours. May be prepared up to two days in advance.