Beer French Onion Gratinee with Garlic Thyme Croutons

Name: Beer French Onion Gratinee with Garlic Thyme Croutons
Ingredients: Soup; 1 large tomato; 2 tablespoons unsalted butter; 2 tablespoons olive oil; 2 pounds yellow onions, thinly sliced lengthwise; 1 teaspoon sugar; 3 garlic cloves, minced; 1 tablespoon flour; 2/3 cup beer; 4 cups vegetable stock (chicken or beef stock can be used also for a more robust flavor); 1 tablespoon dijon mustard; 1 1/2 teaspoons salt; 1/2 teaspoon black pepper; 1 teaspoon fresh thyme; 1 teaspoon balsalmic vinegar; 3 tablespoons parmesan cheese, grated; 8 ounces Gruyere cheese, grated; Garlic Thyme Croutons (recipe below); Garlic Thyme Croutons; 1 small loaf of french bread; 6 garlic cloves, minced (or more if you want more garlicky taste); 1/2 teaspoon fresh thyme, minced; 2 tablespoons olive oil (enough to moisten bread pieces)