Heat the butter in a medium size heavy bottomed saute pan or skillet over Med-High. When the butter is good and hot, add the onions. Coo, UNTOUCHED until fond starts to build up or the onions start to stick to the pan, about 5 minutes. Stir the onions.
2
Continue to stir once every 5 minutes for 20-25 minutes, adding a tablespoon of water to the pan if needed to deglaze the pan (adding water to the pan helps the onions caramelize quicker and helps redistribute the fond throughout the onions.), until the onions begin to take on a deep brown color. If they begin to burn, reduce the heat to Med-Low.
3
Once the onions are browned and caramelized, remove from the heat and use as desired.
Store in the refrigerator for up to 1 week.
