In a large skillet, heat a couple of tablespoons olive oil over a medium high heat.
Add sliced onions, stirring until all onions are coated.
Reduce heat and continue cooking about 10 minutes or so. The onions will soften and begin to get golden brown. Don't worry if they start to stick to the pan and the bottom of the skillet begins to darken, that's how the onions begin to get their golden brown color.
Add sugar and salt about 10 minutes or so into the process. The sugar helps speed up the carmelization process.
Continue cooking stirring occasionally until the onions are a deep golden brown. Set aside.