From my research and surveys, there are essentially two well-known ice-cream parlors in Dar that have stood the test of time. One is Snow Cream, the other is Snoopy.
I tried the mango ice-cream here, and quite liked it. Don't expect world class ice-cream, but do expect pleasantness from the comfort food that it is. A positive service staff attitude was a bonus, but the time it took to deliver three ice-creams, all in cups, was over 15 minutes! And ours was the only car parked outside waiting to be served, a little after 12 on a weeknight.
We were served while sitting in our vehicle. I guess the only downside was that much like most places in Dar, you couldn't expect to not be intruded upon by complete strangers coming too close for comfort to your vehicle. I guess they could have more security for those who wish to eat while parked outside, or not provide that option. But then, Dar has a standard of its own, and it's only fair they be benchmarked against that standard.
If you must go to an ice-cream parlor in Dar, Snoopy will more than likely work well.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.