Mint is very easy to grow. Put it somewhere you don’t mind it running away from. Ours is around the birdbath and has spread into the driveway and adjacent gravel path.
Previous years, I picked mint and dried it. But since I only ever made mint sauce for lamb, I had a brainwave last year and canned it already made. Regrettably I only made 3 half-pints. This year I have made 5 half pints and I may make a second batch.
Here is the recipe I used, loosely based on this one.
4 cups mint leaves, lightly packed (that is, push them down with your hand to about half way, then keep adding mint). To chop, put about 1 cup into a 2 cup glass measuring cup, then use kitchen scissors, points down, to chop up the mint.
Bring vinegar mixture to almost a boil then add mint, simmer 2 minutes. I used 1/2 cup red wine vinegar, 1/4 cup balsamic vinegar, juice of one lemon, and 1-1/2 cups white vinegar, plus 1-1/4 cups white sugar.
My jars are reasonably full of leaves and will be wonderful come December.
Ladle into hot canning jars, wipe edges clean, add lids (I put the sealing lids into hot water in a small bowl for 5 minutes), then process in a boiling water bath for 10-15 minutes. We are at 100 m above sea level here on Port Hope.