Caramelized onions are a great jarred condiment to keep in your pantry. They take about 4o minutes to make, so it's helpful to do a whole bunch at the same time. Add them to any savory dish as a complement, and the flavor is almost guaranteed to improve. They will keep in the refrigerator for 1-2 weeks.
Chop about 6 small red onions into half moons--an amount that will fit well in a 12-in. sauté pan. Heat a pan (avoid nonstick pans) over medium-high heat with about 3 tablespoons of grapeseed oil, add the onions, stir to coat the onions, and season with salt and pepper.
Reduce the heat to low and set a timer for 40 minutes. Give the onions a gentle stir every 10-15 minutes, and watch them slowly break down and melt.
After 4o minutes, the onions should be ready. Add a splash of balsamic vinegar or wine and stir to to de-glaze. Remove the onions from heat and transfer to a mason jar for storage.