Believe it or not, we used canned spinach (because we don't have a food processor / electricity) and we didn't have mustard seeds, but it was absolutely delicious. (whatwouldcathyeat.com)
Fresh spinach tastes a lot better than canned spinach so if you've never tried it go have a bite it's really good! (lifespa.com)
I remember as a kid my mom would roast acorn squash and it was like next on the list next to canned spinach as being one of my least favorite things ever. (theculinarycompass.com)