Ultimate Patty Melts with Bacon

Spread a generous amount of butter on one side of each bread slice and set them aside for now.

Combine ground beef, salt, pepper, and onion powder in a bowl until they are well mixed together. Be careful not to overmix the meat, as this can result in a less-than-desirable texture when it's cooked. Form three patties to fit the shape of each bread slice.

Heat a large non-stick skillet over medium-high heat and add the patties. Cook for 2 to 3 minutes on each side, ensuring they don't break apart during the process. Reduce heat to low and continue cooking until the centers are no longer pink, approximately 5 minutes more. Use an instant-read thermometer to check if the centers have reached a minimum temperature of 160 degrees F (70 degrees C).

While the burgers are cooking, mix together mayonnaise, ketchup, bacon bits, relish, and sugar in a small bowl to create the sauce. Stir until the mayonnaise and ketchup are well combined.

Heat another large skillet over medium-low heat. Place one slice of bread, buttered-side down, in the skillet and top it with two slices of Cheddar cheese, a cooked patty, and two slices of provolone cheese. Spread a thin layer of sauce on the unbuttered side of another slice of bread, and place it, sauce-side down, on top of the provolone cheese. Repeat this process to create the remaining patty melts, working in batches if necessary.

Cook until the bread is lightly toasted and the cheese is melted, approximately 2 to 3 minutes per side.