Bake the cake according to package directions in a 9 x 13 cake pan. Remove and allow to cool for 10 minutes.
Using the end of a wooden spoon, poke holes throughout the cake.
Prepare the lemon pudding mix by whisking the mix and the whole milk together. Immediately pour it over the cake, aiming to fill the holes.
Immediately (don't let the pudding set up!), add the blueberry pie filling over the cake and, using a spatula, gently press the pie filling also into the holes and spread the remainder of the filling smoothly over the top.
Cover the cake and place in the fridge to set up, at least one hour and preferably two.
With a spatula, fold together the completely thawed whipped cream and lemon curd until smooth.
Remove from the fridge and spread the whipped cream over it.