1/2c balsamic vinegar
1/2c good sugar I used coconut sugar
2T lime Juice
1c onion sliced
Place balsamic vinegar, sugar, and lime in a sauce pan and place on high heat. As this mixture cooks watch its viscosity you will see it transform from large bubbles to small bubbles back to large bubbles. Every time a change in the size of the bubbles occurs you will notice a change in its sound. When the large bubbles come back it should be around 270-280 F. At this point you will add the onion to the sauce pot. The moisture from the onions will weep out and the mix will regress to the small bubble stage. Now cook until you are back to the large bubbles and you are good to go.