Blueberry and Rhubarb Shrub Popsicle

Directions

1. Put the rhubarb and sugar in a mason jar (or other non-reactive container with a lid). Seal and shake to combine. Let sit in the refrigerator for at least one day and up to three.
2. After the rhubarb has macerated in the sugar, add the vinegar, stir, and let sit for at least one more day and up to one week. Add a pinch of sea salt. Taste to see if you like the flavor and adjust. When you are satisfied, strain out the rhubarb and keep the liquid, sealed and labeled with the date, in the refrigerator. This is a shrub, will keep for several months, and incidentally is great in cocktails or on its own with seltzer.
3. Puree the blueberries, water, lime juice and sugar to taste. Strain if you like (I don't mind the bits of seed and skin). Chill the puree in the refrigerator until ready to use.
4. Fill the tips of your popsicle molds with rhubarb shrub - for my molds this is a little less than a tablespoon each. You will probably have noticed that it is very tart so I think a little goes a long way - but this should all be adjusted for your taste buds! Freeze until the shrub is nearly solid (about an hour or two). Fill nearly to the top with the blueberry puree (it will expand while freezing) and cover with the popsicle lids. Of course, you could also use the paper cup and popsicle stick method.
5. Freeze until solid, unmold and enjoy (preferably outside on a hot day)!