01 -
Heat up butter on medium-low in a medium pan. Toss in the onions and cook while stirring frequently for 15-20 minutes. Pour in a bit of water now and then to keep them from sticking. Once golden, take them out and cover to keep warm.
02 -
Grab a big bowl and mix ground beef with garlic powder, salt, and pepper. Shape the mix into 8 square patties, keeping their size just bigger than your bread. Aim for about ¼ inch in thickness.
03 -
Clean the pan, then heat it up on medium-high. Fry the patties in pairs for 1-2 minutes on each side. Once done, set them aside.
04 -
Toast four pieces of Texas toast and put them aside for now.
05 -
Stir together mayonnaise, lemon juice, garlic, parsley, ketchup, and pepper in a little bowl to create the spread.
06 -
Take four slices of plain bread. Stack cheese, then a patty, a scoop of onions, and aioli-spread toast. Add more cheese, another patty, more caramelized onions, and finally cap it with a slice of bread. Smear 1 teaspoon of mayonnaise on the top slice.
07 -
Clean the pan and keep it at medium heat. Place the sandwiches mayo-side down. Use a heavy pan to press them flat and cook for around 3 minutes until the bottom's golden. Take the pan off, spread mayo on the top slice, and flip. Let it cook for another 3 minutes or until both sides are browned nicely. Serve while still warm.