Divide the ground beef into 8 equal portions and gently shape into thin patties, being careful not to overwork the meat.
Place one pat of cold butter in the center of 4 patties, then top each with another patty and seal the edges completely to enclose the butter inside.
Make a small indentation in the center of each burger with your thumb, then season both sides generously with salt, pepper, and garlic powder.
Heat a cast iron skillet or grill to medium-high heat and cook the burgers for 4-5 minutes per side for medium doneness, or until they reach your desired temperature.
During the last minute of cooking, top each burger with a slice of cheddar cheese and allow it to melt.
Remove from heat and let the burgers rest for 3 minutes before serving on lettuce leaves with bacon and your favorite sugar-free condiments.