Actually, this is a take-off on her recipe from Nigella Bites. I had Seville (sour) oranges and wanted to make some kind of frozen deal. Her recipe calls for Seville juice, zest and lots of heavy cream. I didn't use ANY cream, but subbed non-fat frozen yoghurt, 1% milk and less than a half cup of 1/2 and 1/2. I froze it in my trusty lo-tech Donvier cranker.
WOW! This is great. About a year ago, I invented (I'd never seen a recipe for it anyway so I'm claiming credit) a marmalade frozen yoghurt/ice creamish deal and it was great. This is along those lines but it's more tart and less bitter (in a good way).
I'll be glad to post the recipe and paraphrase hers if you want to make the full fat stuff.