I keep attempting fried shallots (for toppings, etc) with unfortunate results. I heat some vegetable or canola oil, finely slice some shallots crosswise, and fry them. Unfortunately they over-brown right before they get crispy. The result is a few crispy rings, but most of them are dark brown (nearly black) and bitter and soggy. Should the burner be on a lower setting or higher? I have had it on medium.