Bistro French Onion Soup

Name: Bistro French Onion Soup
Prep time: 10 min
Cook time: 1 h 45 min
Total time: 1 h 55 min
Cuisine: French
Ingredients: 3 tablespoons salted butter; 1 tablespoon olive oil; 10 cups sweet onions (from about 6 onions sliced into half moons); 1 1/2 teaspoons fine kosher salt; 2 cloves garlic (finely minced); 1/2 cup dry white wine (Sauvignon blanc, Pinot Grigio, Chardonnay); 1 tablespoon all-purpose flour; 8 cups beef broth; 1 teaspoon Worcestershire sauce; 1 tablespoon fresh thyme (plus more for serving); 1 bay leaf; 1 medium French baguette; 2 tablespoons olive oil; 8 ounces gruyére cheese (freshly grated)