In a medium bowl, combine ground beef, garlic powder, onion powder, salt, and pepper. Form into 4 equal patties.

Heat a skillet over medium-high heat. Add olive oil and sliced mushrooms. Sauté for about 5-7 minutes until mushrooms are tender and browned. Remove from skillet and set aside.

In the same skillet, cook the burger patties for about 4-5 minutes on one side. Flip the patties, top each with a slice of Swiss cheese, and cook for another 3-4 minutes until the cheese is melted and the burgers reach your desired doneness.

While the burgers are cooking, prepare the creamy herb sauce by mixing mayonnaise, sour cream, Dijon mustard, lemon juice, parsley, chives, salt, and pepper in a small bowl until well combined.

To assemble, place a burger patty on the bottom half of each bun. Top with sautéed mushrooms, a handful of arugula or spinach, and a generous spoonful of the creamy herb sauce. Place the top half of the bun on each burger.