Begin by peeling and slicing your yellow onions into thin, uniform slices, about 1/8 inch thick.

In a heavy-bottomed skillet, add 2 tablespoons of unsalted butter along with 1 tablespoon of olive oil. Heat over medium-low heat.

Once the butter is melted, add the sliced onions to the skillet, stirring gently to coat them.

Add a pinch of salt and cook the onions for 30 to 45 minutes on low heat, stirring occasionally.

After 20 minutes, add a sprig of fresh thyme and a splash of dry wine to enhance the flavor.

Taste and adjust seasonings before serving once they are golden-brown and glossy.