A question about a recipe: Mint Sauce for Lamb

Hi, from the UK. We tend to say 'preserving' rather than canning. Here's how I do it.
Strip the stems from the mint and check the leaves. For 6 cups of fresh leaves - easy to multiple up.
Put the leaves into a food processor with 1.5 teaspoons of granualr (big crystal salt) ir 1 tps of ordinary salt. Blitz until v finely chopped

In a pan hear 2 cups of granulated sugar (I use a bit less - depends on how sweet you like it) plus 2.5 cups of vinegar (I like milder vinegars such a as wine or cider vinegars)+ 6 tablespoons of lemon juice (or more vinegar if you have none. Heat an oven to 150 degrees C and place clean jars in. Put their lids in a pan of boiling water and keep at 80C for at least 10 mins.

When you are ready to go, bring out the jars on a tray (saves Mess) and drain the lids. Pack the jars with chopped mint and return to the over for 2 mins. Bring the liquid to the boil and pour on the liquid carefully. Now take the lids and pop on the jars leaving a little space on the top. As the jar cools you will find that a sterile near vacuum forms at the top of the pot. If you have reactive lids, you will hear the sound of popping. Keeps at least a year.

In the US you can use the traditional hot water bath method if you're more familiar with it.

I haven't tried canning it. I think the mint might get awfully gray.