Grilled Cheese and Tomato Soup Casserole

Ingredients

• Grilled Cheese Sandwiches
• 16 slices sourdough bread
• 8 tablespoons (1 stick) butter, at room temperature
• One 5.2-ounce container of Boursin cheese (or other soft, spreadable cheese)
• 8 ounces fresh mozzarella cheese, sliced into 8 thick pieces
• Tomato Soup
• One 14-ounce can tomato sauce
• ⅓ cup tomato paste
• ½ cup heavy cream
• 1 teaspoon dried thyme
• 2 eggs
• Salt and freshly ground black pepper
• ½ cup shredded white cheddar cheese