Caramelized Onion Tarte Soleil

Name: carmelized onion tarte soleil
Ingredients: 2 large yellow onions (about 1 1/2 pounds total); 1 tablespoon extra-virgin olive oil; 1 tablespoon unsalted butter; 1 teaspoon kosher salt; 4 sprigs fresh thyme; 2 tablespoons balsamic vinegar; freshly-ground black pepper; 2 sheets puff pastry ((I use DuFour, which comes with 1 sheet/box), thawed overnight in fridge); 1 large egg, beaten; 1 (4-ounce) log goat cheese, at room temp.; 1/2 ounce grated Parmesan cheese ((1/4 cup)); hot honey ((optional))

The beauty of this tart is you can fill it with anything you please. I’m using goat cheese and caramelized onions, but you could do anything from a cheesy spinach filling to a sweet one like Nutella. …