French Onion Crostini Posh Pub Grub Made Easy

Ingredients

• 2 tablespoons olive oil
• 3 large yellow onions, thinly sliced
• 1 teaspoon granulated sugar
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 1 tablespoon balsamic vinegar
• 1 teaspoon fresh thyme leaves, chopped
• 1 baguette, sliced into 1/2-inch thick rounds
• 4 ounces Gruyère cheese, shredded
• Fresh parsley, chopped (for garnish)