Sautéed red onions, caramelized in butter and olive oil on the stovetop. The key is cooking them on low heat, stirring often until they caramelize! This recipe makes 1 cup caramelized onions.
Cut the stem and root ends off each onion, and then cut the onion up into 1/4"–1/8" thick slices.
In a large skillet over medium heat, add olive oil and butter, letting the butter melt. Add onion slices and a pinch of salt on top, stirring to fully coat the onions in butter and oil. Cook until onions become translucent, about 7-8 minutes.
Reduce heat to low and continue to cook the onions until they caramelize. Stir every few minutes with a spoon or a pair of tongs until they start to soften and you see their rich color change. This takes about 25-30 minutes. During this time the onions will stop releasing water and they might stick to the skillet, if this happens add a tablespoon of chicken broth and stir to prevent burning. Repeat as necessary.
Serve right away, keep in the refrigerator for up to 4 days or freeze for up to 6 months.