Yoke's | French Onion Soup

Ingredients

• 4 tbsp unsalted butter
• 1 tbsp vegetable oil
• 5 medium-sized sweet onions (about 3 pounds), thinly sliced
• 3/4 tsp salt
• 1/2 tsp black pepper
• 3/4 tsp sugar
• 1 cups dry white wine
• 2 tbsp flour
• 6 cups beef broth
• 1 tsp Worcestershire sauce
• 1/2 tsp dried thyme
• 2 bay leaves
• 1 baguette, cut into 1/2 inch slices
• 1 tbsp dry sherry
• 8 oz Gruyére cheese, grated (about 2 cups)
• 1/2 cups grated Parmigiano Reggiano