Combine all ingredients in a medium saucepan and stir to combine.
Cook covered on medium heat until the cherries and onions have softened, about 20 minutes.
Transfer to a blender and puree (slowly and carefully, hot foods can spurt out) or puree with an immersion blender.
Return to the pot and cook, uncovered, until the mixture is reduced by approximately half and is nicely thickened, 30-40 minutes.
Taste and adjust salt or pepper, as needed.
When it’s finished, ladle the sauce into prepared jars. Wipe rims, apply lids and rings and process in a boiling water bath for 15 minutes (see note).
Notes
Makes about 1 pint (I did 1 half pint and 2 half cup jars. The half cup worked perfectly to dilute with water and brush on a cut up chicken (with a little left over for dipping).If you double the recipe and puree with a (non-immersion) blender (carefully), you should do it in batches.Canning instructions assume you know how to can. If not, you can freeze the sauce or store in the refrigerator and use promptly--or check out canning lessons at Food in Jars.
I am not a health professional and nutrition data is calculated programatically. Accuracy may vary with product selection, calculator accuracy, etc. Consult a professional for the best information.