Put it all in a small saucepan and bring to a boil.
Turn down the heat to a low simmer for 15 minutes.
Turn off the heat and let it sit for 20 minutes or more.
Strain it into a 2 cup glass (borosilicate/Pyrex) measuring cup, and add water to make the total volume 1½ cups. (This is to avoid it being way too sweet if a bunch of water boiled off in the simmering)
Store it in the fridge.