In a large bowl, gently combine the ground sirloin, onion powder, garlic powder, salt, and pepper. Be careful not to over-mix, as this can make the burgers tough.

Divide the mixture into 4 equal portions. Shape each portion into a ball, then flatten them into discs, making them slightly thinner in the center.

Heat a large skillet over medium-high heat. Add the butter and swirl the pan to ensure the bottom is coated.

Cook the burger patties to your desired doneness. Since sirloin is quite lean, it's recommended to cook them to medium-rare doneness, which corresponds to an internal temperature of 140°F. This usually takes about 3 minutes per side, but adjust the cooking time based on your preferred level of doneness.