This makes enough syrup to fill most of a regular-sized mason jar with fruit leftover for a cordial. Mix the syrup with ice water, club soda, or a cocktail for a drink, or pour onto waffles or ice cream. It might also be a tasty dressing for fruit salad. As an alternative, you could try adding pectin and see if it makes a jam!
Serviceberries are common around the Midwest and ripen to deep reddish-purple in late May / early June. They don’t have a very strong flavor, a bit like a mild blueberry with lots of tiny seeds. You can eat the seeds, though they are tougher than blueberry seeds and you might prefer to strain them off.
This is a good way to use up red wine that is turning to vinegar. I typically save the last bit of box wine to use as vinegar when it starts to turn. It’s not nearly as vinegary as buying a bottle of red wine vinegar and whatever alcohol is still in there cooks off, leaving a slightly grape-ier flavor. The rhubarb gives it a bit more tang to keep it lively.
~1 pound fresh serviceberries
1 stalk rhubarb (maybe 18 inches long)
2 cups sugar
2 cups water
1 cup stale red wine/red wine vinegar
1-2 tablespoons lemon juice
2 big springs of fresh mint
Add the serviceberries, sugar, and water to a medium-sized saucepan and cook on medium heat, stirring to dissolve the water. Use a potato masher to mottle the berries so more flavor comes out.
Chop the rhubarb into small-ish pieces and add to the pot, stirring occasionally as it begins to boil. Add the wine/vinegar and lemon juice.

Continue to simmer at a low, rolling boil, skimming off the foam and stirring periodically. When more of the liquid has cooked off, test a few drops on a cold saucer and hold the saucer up. If the syrup moves slowly across the saucer, it’s probably done enough. Remove the pot from the heat and add the mint sprigs, poking them down in until they wilt.
Let it cool, then pour over a strainer into a bowl or a wide-mouthed measuring cup.