Once the recipe is reduced it will mound on your spoon and will be an amazing pair for cheese platter, bruschetta, and an upscale sauce for burger or steak. The recipe below is an adaptation of the original to upgrade for safe canning practice.
Balsamic Cherry Tomato Caramelized Onion Conserve
2 T. olive oil
2 pounds sweet onions (3 large, quartered and thinly sliced)
1 t. sugar
4 cups halved cherry or grape tomatoes (measure after halving)
¾ cups honey
¼ cup balsamic vinegar
½ t. freshly ground black pepper
Preparation : Prepare 8 half pint jars, lids, and rings. Sterilize the jars and keep them in the hot water till its time for processing. Make sure to fill your water bath canner and get the water to a simmer.
Cooking: In a large skillet or enameled dutch oven add oil, onions, and sugar. Cook covered for 13 to 15 minutes on low heat, stirring occasionally until onions are tender. Uncover and cook on medium until onions are golden brown. Stir in the cherry tomatoes and honey to the onions. Bring to a boil over medium heat for 5 minutes or until the tomatoes are soft, stirring often until thick enough to mount on a spoon. Remove from heat add balsamic and pepper.
Filling the jars: On a dishtowel place your hot jars and using your funnel in each jar ladle the mixture into the jars leaving 1/4” headspace. Remove air bubbles and refill to the proper headspace if necessary. Taking a clean papertowel wet it with warm water and wipe the rims of the jars removing any food particles that would interfere with a good seal. Using your magic wand extract the lids from the hot water and place them on the now cleaned rims. Add your rings to the tops of each of the jars and turn to seal just "finger tight".
Processing: Make sure your rack is on the bottom of the canner and place the jars in the water bath making sure that the water covers each of the jars by 1 to 2 inches. Add hot water to the canner if it doesn't measure up. Cover the pot and turn up the heat under the canner and wait for the water to start boiling. Once the water has come to a boil start your timer for 10 minutes. When complete turn off the heat and remove the cover and let the jars sit for another few minutes. Remove the jars and place them back on the dishtowel in a place that they will sit overnight to cool. Do not touch or move them till the next morning.
Sealing: Some time in the next hour your jars will be making a "pinging" or "popping" noise. That is the glass cooling and the reaction of the lids being sucked into the jar for proper sealing. Some recipes may take overnight to seal. Check your lids and reprocess any jars that did not seal.