Mix the dry onion
soup mix into the sour cream to create California dip.
Heat the spinach. Turn it into a colander or strainer; press
as much liquid out as possible. Combine the drained spinach
and the sour cream mixture.
At this point, the spinach may be held, carried to a potluck
and reheated just to serving temperature -- any more may
curdle the sour cream, which will detract from the appearance
though not the taste.
Low-fat sour cream is fine; I haven't tried this with non-fat,
but it should probably work out well, since the onion flavor
predominates. Half low-fat and half non-fat should certainly
In theory, there's no reason not to use some other flavor
of soup or dip, but most other flavors aren't as robust as
Garnish can be anything you like; I've used slices of hard-cooked
eggs; a handful of frozen corn, carrots, or mixed vegetables;
croutons; cracker crumbs; or onion rings.
IF you have any left over -- I never have, but it's theoretically
possible -- it makes an excellent omelet filling, and would
probably be okay as an ingredient of spinach quiche.