We have made this a few times now. YUMMY! Couple of things we did:
* we took tails off shrimp, too much work to do while eating
* the first time we made it, we forgot the cheese, and we loved it so much, we decided not to add it.
* we used frozen asparagus spears (trader joe's have the best tasting ones in our opinion) run them under water for a few minutes, cut into pieces, and then put them at the bottom of the colander when rinsing the pasta.
* being in the northeast, lemon zest is not cheaply come by, so, in its stead, we used a dash of lemon juice into the mixture.