Prepare the Onions - Cut the ends of the onions and peel the outer layer. Then, slice them into ¼-inch slices from the root side to the end ( along the natural grain visible on the outer layer of the onion).
Heat the pan - Set the saute pan on medium-high heat and add butter. Keep an eye on the heat; you don’t want the butter to turn brown.
Add the onions - Separate the slices and toss them into the melted butter, then saute for a few minutes.
Sprinkle salt over the onions – When the onions have turned translucent and lightly soft, add some salt to release moisture.
Turn down the heat – Let the onions cook on a low heat setting for 25 -30 minutes.
Stir the onions – Every 5 minutes, but avoid moving them around the pan too many times. Hence, a slight swirl around the pan with a wooden spoon will be sufficient each time.As a result, the slices on the top layer will need an equal chance to sit at the bottom of the pan, where they will caramelize the most. After 25-30 minutes, the onion slices should have turned medium brown to dark brown around the edges and at this point, they will be fully caramelized.