- 1-1/2 tablespoons unsalted butter
- 2 pounds onions, peeled and very thinly sliced
- Sea salt and freshly ground black pepper
- Melt the butter in a large, heavy skillet over medium heat. Add the onions, stir so they are coated with butter, and reduce the heat to medium-low. Cover the skillet and cook, stirring occasionally to be sure the onions aren't sticking, until they are reduced in volume by two-thirds and are a pale gold color, 1-1/2 hours. Continue cooking, stirring often, until they melt by another one third and turn a deeper golden, 10 to 15 minutes.
- Remove the skillet from the heat, season the onions with salt, and pepper if desired, and let cool. Serve alongside roasted meats or fish, as a topping for pizza or a filling for savory tart.