Step 1

Slice steaks in half, then into strips about 1/4-to 1/2-inch-thick. Place in a bowl and cover with plastic wrap. Freeze until very cold and firm, but not quite frozen, about 30 minutes to 1 hour. Place blue cheese in the freezer as well so it's easier to handle.

Step 2

Chop the partially frozen steak with a sharp knife or meat cleaver until it resembles coarsely ground meat. Crumble about 1/2 cup (unpacked) blue cheese on top; use the cleaver to fold and chop it into the meat.

Step 3

Lightly dampen your hands with water and roll the mixture into 3 or 4 patties. Flatten onto individual pieces of plastic wrap; seal and refrigerate until ready to cook.

Step 4

Unwrap patties and continue pressing them to your desired thinness. Season both sides with salt and pepper.

Step 5

Heat a dry cast iron pan over medium-high heat until very hot. Sear each patty, without disturbing it, until a crust forms on the bottom, about 3 minutes. Flip and continue cooking until the surface springs back when lightly pressed, about 3 minutes more.

Step 6

Spread some mayonnaise over each bottom bun half. Serve patties on the buns, topped with pickled red onions.