Wash blueberries well, and pick off all the stems.
Place berries into a heavy saucepan, and add 1/2 cup of water and sugar. Stir to dissolve and cook on medium high heat.
2 cups blueberries, 3/4 cup water, 1/2 cup sugar
Bring to a boil, then turn down to a simmer.
While mixture simmers, mix together cornstarch and remaining 1/4 cup of cold water with a fork.
2 tablespoons cornstarch
Slowly pour cornstarch mixture into syrup, stirring constantly while you do so to ensure it all gets mixed in.
Continue simmering for a total of 15 minutes or until the syrup has gotten to the thickness you desire. Add the lemon juice and stir to incorporate, then remove the syrup from the heat.
Taste your blueberries before making this. If they're a little tart, add some extra sugar. If they're good and sweet already, follow the recipe and taste test at the end to see if you need to add a teaspoon more at a time.
Because I like the idea of whole blueberries in my syrup to add a rustic and homemade touch, I immediately place into clean jars rather than straining out the whole blueberries. I recommend doing the same. You can puree the syrup if you prefer or strain it to remove the blueberries.
For more tips and tricks, be sure to read the full article above.