A great addition to any meat dish, but especially on burgers! Learn to make caramelized yellow onion with marsala. Marsala wine adds a rich flavour depth to caramelized onions.
Peel and cut the onions in half, then proceed to slice them all up in rather thin slices (1-2 mm thick).
Set a skillet on medium-high heat and melt the butter.
Add the onions and sauté on medium-high heat constantly stirring to ensure the heat is distributed evenly.
After a couple of minutes, add a pinch of salt to the onions. This will draw out some of the moisture. Keep sweating the onions on medium-high heat for about 10 minutes, until soft but not browned. If the onions are browning, lower the heat and keep stirring them.
Lower the heat to medium and add the sugar. Stir for a couple of minutes, the sugar will start to melt.
Pour in the marsala ans stir for a minute. Cover with a lid and let simmer on low heat for another 15 minutes, checking from time to time. The onions will absorb the marsala. If the liquid is reducing too fast, lower the heat.
Remove the lid and give the onions a stir. Increase the heat to high to help evaporate any excess liquid left. Add one small slice of butter to the mixture to kick back the caramelization. Keep stirring on high heat for a couple of minutes until the mixture gets a slightly sticky texture. Transfer to a serving bowl or a jar.
Because of its butter content, this marsala onion relish tastes best when lightly warm. If storing in the fridge before use, microwave for a few seconds for best results.