Ultimate Gourmet Grilled Cheese

Name: Ultimate Gourmet Grilled Cheese
Total time: 40 min
Yield: 4 servings
Ingredients: 8 slices bread good quality, I used thick cut Artisan bread; mayonnaise for spreading; 12 ounces gruyere cheese sliced thinly OR grated, at room temperature; 6 ounces white cheddar cheese sliced thinly OR grated, at room temperature; 4 slices muenster cheese thin, at room temperature; 2 yellow onions diced; 1 teaspoon fresh thyme minced; 2 teaspoons fresh rosemary minced, divided; 1 teaspoon brown sugar; salt; pepper; 3 tablespoons butter divided; 1 tablespoon olive oil