In a mixing bowl, mix together the ground beef, onion powder, garlic powder, salt, and pepper. Once well combined, divide the mixture into 6 equal portions and shape each portion into a patty.

Heat a skillet over medium heat and add the patties. Cook them for 4-5 minutes on each side, or until they are cooked to your liking. Once done, take the patties out of the skillet and set them aside.

In a small bowl, mix together the mayonnaise, chopped bacon pieces, ketchup, sugar, and relish until combined.

Spread butter on one side of each slice of rye bread. On the unbuttered side of 3 slices of bread, place a slice of cheddar cheese, then add a cooked beef patty. Spread some of the secret sauce on top of each beef patty. Top with a slice of provolone cheese, then cover with the remaining slices of bread, buttered side up.

Heat a clean skillet over medium heat and add the assembled sandwiches. Cook for 2-3 minutes on each side, until the bread is golden brown and the cheese is melted. Once cooked, remove the patty melts from the skillet and serve immediately.