Cut short ribs into approx 1" by 1" portions.
Place on plate or tray in freezer for 15-20 minutes.
Place a large bowl under food grinder. Place each portion into food grinder one at a time and process into ground beef at medium seed.
OR if using food processor: add beef portions to food processor and process on high for 20 seconds. Depending on size of food processor you might want to do half at a time. Remove to a bowl.
Form loose approx 3 oz balls from the ground beef. Don't pack too tightly.
Place each ball on a piece of parchment paper. Fold over to cover or use separate piece of paper on top.
Using a flat pan or spatula press the ball down to form flat patties (pictures and notes in post). *This method keeps your kitchen from becoming extra smokey while cooking but yields same great burger taste.*
Place patties on parchment paper lined baking sheet in the refrigerator.
To make burger sauce, in a bowl add mayo, shallot, garlic, ketchup, sriracha, mustard, bread and butter pickles, salt and pepper. Blend using an immersion blender until smooth. (See note if you don't have an immersion blender.) Place in refrigerator until ready to serve.
Prepare toppings of choice.
Heat cast iron skillet over high heat.
Butter the buns and set them butter side down on the cast iron until golden brown. Remove to a plate.
Heat oil in cast iron. Meanwhile season one side of burger patties with salt and pepper.
Place the burger patties S&P side down in the cast iron skillet. You will probably have to work in batches. Season the other side with S&P while cooking. Press down on burger with spatula. Cook for 1 ½ minutes.
Flip burgers, add sliced American cheese and cook for 30 seconds on the other side.
Build your burger. Place burger on toasted bun. Recommend making these double cheeseburgers but a single is fine as well. Add toppings then drizzle with burger sauce.