Ingredients

• 3 tablespoons unsalted butter

• 1 1/2 pounds yellow onions (about 3 medium), thinly sliced (about 6 cups)

• 2 teaspoons fresh thyme leaves divided, plus more for garnish

• 1/2 teaspoons black pepper, divided, plus more for garnish

• 1/2 teaspoons granulated sugar

• 1 3/4 cups lower-sodium beef broth, divided

• 4 (4-ounce) chicken breast cutlets

• 1/3 cup all-purpose flour

• 2 teaspoons onion powder

• 1/2 teaspoon kosher salt

• 1 tablespoon olive oil

• 1/4 cup dry sherry

• 1 tablespoon beef bouillon paste (such as Better Than Bouillon) 

• 4 ounces Gruyère cheese, shredded (about 1 cup)

• 1 ounce Parmesan cheese, grated (about 1/4 cup)

• Crusty bread, for serving