Thanks, Kevin. I'll have to try this too and expand my spinach options.
For those counting calories, the roux version is adaptable to use any dairy you'd like:
I usually blanch the spinach quickly. Drain and squeeze out excess liquid. Saute some shallots in butter, add some flour for a white roux, then add some milk, half-and-half, or cream. Even (gasp) fat-free half-and half works well. Season the bechamel with salt, white pepper, and a pinch of nutmeg. I usually chop the spinach very fine and stir it in. Sometimes I put the bechamel into a processor with the spinach to mince the spinach finer. Reheat or keep hot in a double boiler.
Those on a lowfat regimen can even use skim milk. Whisk some skim milk into enough flour to thicken the sauce (about 3 tablespoons per cup, but you'll have to play with that). Heat the milk-flour mixture, whisking constantly, until thickened and simmer a few minutes to cook the flour. Naturally, this won't be as luscious but it's still quite good.
Rita