1. In a large mixing bowl, combine the ground beef, Parmesan cheese, minced garlic, salt, and black pepper. Use your hands to gently mix until the ingredients are just combined. Avoid over-mixing to keep the burgers tender.
2. Divide the mixture into four equal portions and shape each into a patty about 3/4-inch thick. Make a slight indentation in the center of each patty to prevent puffing during cooking.
3. Heat a grill or skillet over medium-high heat. Brush the grill grates or skillet with olive oil to prevent sticking.
4. Place the patties on the grill and cook for about 4-5 minutes on each side, or until they reach your desired level of doneness. If using cheese slices, add them during the last minute of cooking to melt slightly.
5. While the burgers cook, toast the hamburger buns on the grill until golden brown, about 1-2 minutes.
6. Assemble your burgers by spreading mayonnaise on the bottom half of each bun. Layer with lettuce, a burger patty, tomato slices, and red onions. Top with the other half of the bun.
7. Serve immediately and enjoy the burst of flavors!

Remember, cooking is an adventure. If you’re feeling adventurous, toss some sautéed mushrooms or caramelized onions onto your burger for an extra layer of flavor. Just like my travels have expanded my culinary horizons, don’t hesitate to explore new ingredients and techniques.