Depends what you want. I don't live in Des Moines, but when I am forced to go there, I know a couple of places. Des Moines really struggles for a MSA of its size. I usually end up eating in a member only place due to this.
For somewhat authentic Sicilian, Tumea and Sons gets their inputs from Graziano Brothers, so it is o.k. for Americanized Italian / Sicilian, and probably the best and closest thing Des Moines has to offer.
Restaurant:
https://www.tumeaandsons.net/
Buys inputs from:
https://grazianobrothers.com/
With respect to steak in Des Moines, there are numerous places that most don't know about, but the issue is they are private, or semi-private.
Cedar Rapids and the surrounding area have an abundance of places, as shocking as that is. Unfortunately, most don't know about them, so many come and go, and it's hard to keep track of what's open.
Italian you'd need to go to Vino's. No Vito's, but Vino's. Sal had a place downtown, but I think he got chased back down to St. Louis, and he's on The Hill now.
Steak, you'd need to go to Moline, but that trip is worth it. Bring your wallet. They have really, really good steak at $32 per ounce. Which is actually very reasonable given what it is.
So Italian:
http://vinosristorante.com/
Steak:
https://www.bassstreetchophouse.com/
For what I classify as more "uppity" "nouveau riche":
https://cobblehillrestaurant.com/
And there are a whole bunch of hole in the4 wall places where surprisingly you can get fresh Mako Shark, shark tenderloin, Wahoo, John Dory, Dolphin Fish (incorrectly called Mahi in the USA), Scottish Salmon, which for whatever reason is extremely difficult to get in the Midwest, etc., ad infinitium...
But best dish, best restaurant is largely subjective, and largely predicted on disposable income. As an example, I don't mind paying $192 for a 6 oz steak at Bass St Chop House, but it irritates me to pay $25 for crappy Italian in Des Moines, or what passes for steak in that town.