Caramelized Onion Tart with Gorgonzola

This delicious hors d’oeuvre or first course was devised by my friend Bonnie Stern, Canada’s foremost authority on food and cooking. I’ve taught many times at Bonnie’s cooking school in Toronto, though I first tasted this tart in New York at an event promoting Canada. It’s a little like a focaccia, but here puff pastry substitutes for the yeast dough.