Caramelized Onion without vinegar back

Cooking spray 3 1/2 cups chopped onion 2 ounces Gruyère cheese, shredded and divided 2 tablespoons chopped fresh chives, divided 1/3 cup canola mayonnaise 1/3[...]

1 tablespoon unsalted butter 1 small onion , sliced thin 1 tablespoon brown sugar 1 cup unbleached all-purpose flour 2 teaspoons baking powder 3/4 teaspoon[...]