Golden Onion Soup

• 2 tablespoons unsalted butter
• 2 tablespoons olive oil
• 1 1/2 lbs onions, sliced
• 1/2 lb red onion, sliced
• kosher salt
• pepper
• 1 tablespoon all-purpose flour
• 2 tablespoons balsamic vinegar
• 1 cup dry white wine
• 6 sprigs fresh thyme, plus more for serving
• 2 cups low sodium beef broth
• 2 ounces gruyere or 1/2 cup gruyere, grated

1. Heat butter and oil in a large pot over medium heat. Add onions, season with 1/2 teaspoon each salt and pepper, and cook, covered, stirring occasionaly, until very tender, 12 to 15 minutes.
2. Reduce heat to medium-low and cook, uncovered, stirring occasionally, until onions are golden brown, 20 to 25 minutes.
3. Sprinkle with flour and cook for 2 minutes; stir in vinegar.
4. Add wine and simmer for 3 minutes. Add thyme, broth, and 4 cups water and bring to a boil. Reduce heat and simmer for 10 minutes. Spoon soup into bowls and sprinkle with cheese and aditional thyme, if desired.
5. TIPS & TECHNIQUES.
6. MAKE-AHEAD TIP: Freeze the soup (without cheese) for up to 3 months. Thaw in the fridge overnight. Reheat, covered, in a saucepan over medium heat. Top with chese and additional thyme before serving, if desired.

unsalted butter, olive oil, onions, red onion, kosher salt, pepper, flour, balsamic vinegar, white wine, thyme, beef broth, gruyere

Taken from www.food.com/recipe/golden-onion-soup-495597 (may not work)