I was following this kind of method:

Since I don’t have a separate griddle, I just use my cast-iron pan. It’s kind of finicky since the patty wants to stick to the pan and my spatula which tears the patty apart. I still haven’t got it down perfect but my second double burger ended up better than the first.

I don’t follow how he cooks it exactly - after flattening, I season with salt and pepper and throw on a bunch of finely diced onion. I smash the onion into the patty a bit, flip once, make sure you get that nice crust on both side, and I used a brioche bun. I didn’t feeling like chopping any other veg so I topped it with ketchup and a bit of smoked jalapeno hot sauce.

Now that I know how easy this is, my ass is going to become soooooooo fat.