Can't help with a recipe, Nannyconnie, but if you good Mint Jelly recipes there seem to be quite a number and they mostly seem to include apple - I suppose to make it set.

I haven't got mint in my garden, but when I buy fresh mint, there is usually more than I need, so I freeze it and it is fine for using in any recipes. It's great for using in mint sauce as you can crumble it easily when it's frozen.

Hope this helps.