You could try using gelatin but it's a little harder to work with than konjac or xanthan gum.

It's the extract powder with nothing else added (many add erythritol or allulose to make it measure like sugar).

SRY - I'm 77 and having to learn to cook for two . . .

Thank you so much. Excited to make this and can it for winter.

From what I've read, you can can sugar-free fruit syrups at home successfully. There's also a fair amount of natural sugar in the blueberries as well.

Lemon juice adds a little flavor and tartness as well as acting as a preservative for the fruit.

Didn't think about using water. I sauteed mine in grassfed butter. I use the frozen blueberries. I put in stevia and just a little salt. I guess the frozen blueberries would be the same as using water. It seems to give off water. What is the purpose of lemon juice?

What is your recipe with the heavy whipping cream?

You can definitely use just one sweetener, but I find combining 3 or more sweeteners works best. The sugar sub is a monk fruit and erythritol blend so adding in stevia helps round out the flavors.