I used frozen spinach and won't do that again because the water content was ridiculous. I ended up lining a strainer with a coffee filter and draining but even after it seemed as though I had strained as much as I could, it still was somewhat swampy when I pressed it. I ended up talking small handfuls and squeezing the bejeebers out of it....ended up with an extra 3/4 cup of spinach juice in the bowl, so I'm sure if I hadn't done that, the final result would have been soup.
The next time I make this, I'll definitely eliminate all salt. I should have paid more attention to the reviewers who mentioned it was too salty. If I used a different cheese - like swiss? - maybe it wouldn't have been such a problem.
This is so thick and delicious, though, that I think I'll be able to convince my son-in-law to ditch his favorite spinach casserole recipe that uses Pepperidge Farm stuffing mix and replace it with this.