Put all ingredients in a medium to large saucepan.
Whisk to combine in the pot, and then turn on the stove to low heat or medium heat (not high heat!). Never leave this at a full boil. You want a nice, slow simmer. Skim any foam off the top, if there is any.Cook for about 1 to 1 ½ hours, stirring every 10 minutes or so and skimming the foam off the top if needed.After about an hour or so, you will notice that the mixture has greatly reduced and gotten considerably darker (depending on sweetener used) and thicker. At this point, you can turn it off.
Allow to cool for a bit and then transfer to a glass jar. Chill overnight in the fridge (It will thicken as it cools). Serve chilled or at room temperature.
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Notes
Please note that the nutrition data given here is a ballpark figure. Exact data is not possible. Data is for the entire batch. Yield will vary from batch to batch depending on how much it cooks down before it thickens.