Heat oil in a small saucepan placed over medium-low heat. A slice of onion should just sizzle a bit when added to the hot oil. Add 1/2 of the onions and cook, stirring occasionally, until the onions are a deep golden brown, about 7-10 minutes. Remove with slotted spoon to paper towels to drain, and salt to taste. Onions will be soft at first and will crisp as they cool. Repeat with remaining onions. Add additional oil if necessary. Serves 4