Prebake the shell until crisp, 10 to 12 minutes. Meanwhile, heat the oil in a large skillet over medium heat. Add the onions and sprinkle with the salt. Cook, stirring, until the onions are wilted ...
Place a piece of aluminum foil into the tart shell and weight with pie weights, uncooked rice, or dried beans. Prebake the shell until crisp, 10 to 12 minutes. Meanwhile, heat the oil in a large ...