14 g (1 T) butter 10 g (1 T) olive oil 225 g (1⁄2 pound) onions, 1⁄2-inch dice 15 g (1 T) brown sugar 1 g (1⁄4 t) kosher salt 60 g (4 T) balsamic vinegar (don’t waste D.O.P. balsamic here; I.G.P. is fine!) 10 g (3 T) thyme
Add the butter and olive oil to a sauté pan and melt over medium heat.
Add onions, reduce heat to medium-low, and cook until caramelized, about 60 minutes. Add a few tablespoons of water if the onions get too dry. Adjust the heat so they don’t fry. You’re looking for more a translucent brown color, not a dark fried brown.
Add the brown sugar, salt, balsamic vinegar, and thyme to the onions and reduce to a syrup. Reserve in the refrigerator until ready for use.