Wash and clean the fruit, then put into a pot with the water and bring to a simmer for 10 minutes.
Smash the fruit or pulse with a handblender to break them up.
Pass the mixture through a sieve or food mill to extract the pulp.
You can add a little extra water to the pulp and put it through the food mill a second time to get as much as possible.
At this point I like to put the fruit puree in a highspeed blender for a smooth texture, but you don't have to.
Put the puree into a wide pan and bake at 300 F, whisking occasionally until thickened, about 30 minutes. I like to add a pinch of salt and sugar or maple syrup as a preservative.
Transfer the puree to a container and freeze until needed, or It will hold in the fridge for a week. Use the puree in baked goods, quick breads, and other desserts.
Video
Notes
You can make the puree with frozen or fresh fruit.