Mama's Best Broiled Tomato Sandwich

INGREDIENTS

• 2 tablespoons olive oil
• 2 tablespoons balsamic vinegar
• 4 ripe tomatoes, sliced
• 3 tablespoons mayonnaise
• 1/2 teaspoon dried parsley
• 1/4 teaspoon dried oregano
• 1/4 teaspoon black pepper
• 3 tablespoons grated Parmesan cheese, divided
• 4 slices bread, lightly toasted