This doesn't use up fresh things from the garden, etc, but it's a nice and easy thing to make from your larder.

Take one largish tin of crushed pineapple.   Pineapple pieces or chunks can be used  if you whizz them in the blender or food processor.   If they are in syrup instead of natural juice, you need to pour the syrup away otherwise it will not work.  In fact I prefer to pour some of the juice away although not all of it.   (The juice can be drunk or used in some other drink or food.)

Mix the pineapple bits with one normal tin of evaporated milk.   Stir it well, the reaction will happen as you mix it.   It does not curdle (which is what most people would think it would do) but it does thicken.

You can top this with maraschino cherries or crushed nuts.   Or leave plain.