Bake cake according to package instructions in an 9x13 in baking pan. Allow cake to cool for at least 30 minutes.
When cake is almost cool, whisk together lemon curd, instant pudding, milk, and poppy seeds. Set aside.
With the end of a long wooden spoon make holes all over the cake. The holes should be spaced and reasonably deep.
Spread the lemon mixture over the top of the cake. Cover and set in the fridge for 45 minutes.
Remove cake from fridge and top with the whipped topping. Garnish with crushed cookies and white chocolate chips.
Store covered in the fridge when it is not being served.