15 cups of cubed fresh rhubarb
7 cups sugar
Put sugar and rhubarb in a large stockpot. Mix, so sugar has coated all the rhubarb.
Let it set on the counter for 2 hours, to give the sugar time to pull out much of the moisture from the rhubarb.
When 2 hours have lapsed, move the pot to the stove and cook on medium to med-high heat until much of the rhubarb has dissolved and mixture becomes thick, almost the consistency of a chunky tomato sauce. (See video below) This will take about 15 minutes or so.
NOTE: Be sure all jars are sterilized before using and if canning, lids and rings are hot, and jar rims are wiped clean before processing in a water bath.