1. Preheat grill over medium-high heat. In a large bowl, gently combine the beef, cottage cheese, steak sauce, garlic, salt, and pepper with your hands. Lightly form the mixture into 4 even patties, about 1/3 inch thick.
2. Cook burgers for 4 to 5 minutes per side or until cooked at least to medium doneness.
3. Remove the burgers to a plate, cover with foil, and let rest for 5 minutes. Serve on buns with onion and arugula. Serve condiments on the side, if desired.
Though steaks can be cooked medium rare, it's important that ground beef be cooked a little longer, to at least medium doneness. How do you know when it's cooked properly? Use a meat thermometer. To help prevent food borne illness, these ground sirloin burgers should reach an internal temperature of at least 160ºF.
Cook burgers inside instead of outdoors. Place nonstick sauté pan over medium-high heat. Cook burgers (in batches, if necessary) for 3 minutes per side, or until at least medium doneness. You'll probably need to use the kitchen fan for this preparation. Or preheat broiler. Cook burgers on broiler pan under the broiler for 2 minutes per side, or until at least medium doneness.