Unless you put up sour cherries in season last summer (I didn't) your choices come January are limited to tinned pie filling (ick) a filling made from tinned cherries (expensive!) or a filling made from frozen cherries. The latter, while still expensive is less so than tinned, and the overall quality of the fruit is better. I spent about eight dollars for two bags which yielded eight cups. Do the maths (go on, this is simple for heaven's sake) and you come out ahead over the six dollar tin of sour cherries in juice of which you would need at least four.
The beauty of this recipe is how wonderfully it freezes. You'll have enough for a generous pie, but if you're using it for an extravagant birthday cake filling (Happy 52nd Mr. ETB) freeze the rest in small plastic freezer bags or jars, and you'll have a perfect pancake topping ready to go some Sunday morning when you don't feel like dealing with breakfast. Or ice cream-you can use it to top ice cream. Or tarts. Well, you get the idea.
You don't need to fully thaw the cherries, which also make it that much easier. The recipe isn't fancy, but it is reliable. When you're assembling a fancy chocolate and whipped cream cake, you don't need unreliable cherry filling, now do you? Of course you don't-that's why you came here. This reliable recipe is from the ever reliable Ball Blue Book.
You Will Need:
8 cups frozen sour cherries
2 1/2 cups sugar
5 tablespoons cornstarch
Mix cornstarch and sugar together. Toss with cherries in a large bowl and let stand about 30 minutes(up to 45 if the cherries are really frozen hard). I give them a gentle toss with a spatula a few times to help distribute the cornstarch/sugar mix as the cherries thaw, but you don't need to.
Cook over medium heat in a large, heavy pot, stirring gently to prevent scorching before the sugar melts. Cook until thickened (I like mine a bit on the looser side, but if you like a thicker filling cook a bit longer). Cool, then pack into freezer containers and freeze. Makes about 4 pints.