Of all of the infinite varieties of hamburger I think that sliders are my favorite. There is just something about the little bombers that perfectly captures the happy confluence of beef, bun and cheese. The slider is the reduction of the burger to its ideal form, allowing one, in the words of Burger Guru George Motz, to hold a coffee and cigarette in one hand and the burger in the other. Living in the middle of NYC I have easy access to some wonderful burgers in almost limitless varieties but when it comes to sliders the options are few and far between, at least if you want the best of the breed. My personal favorite in NYC is Shopsin's sliders in the Essex Street market but they have a rather limited schedule, closing early. Of course there is always White Manna in Hackensack but this requires leaving the city.
So I have found the next best alternative is to make them myself. Using the above video as inspiration I have tried several methods but this is the technique that comes closest to the Holy Grail in my mind.
Martin's Famous Potato Dinner Rolls (the perfect size for sliders)
Thinly sliced white or yellow onions
2-3 tablespoons of beef broth (water or white wine also work but the beef broth adds a little extra flavor)
Salt to taste
To begin with pre form your patties in to small 2-2.5 oz balls. I generally use a straight chuck with a 75/25% meat to fat ratio but obviously feel free to use your preferred mix. Let the beef come to room temperature before cooking. Season with salt.
I use a cast iron skillet that I heat up for a good ten minutes on a medium to high setting, this will assure that the pan retains its heat through out the cooking process. You want the beef to sizzle when it hits the pan but not char to the degree that a one world want on a steak.
Next take your trusty spatula and mash down the onion/patty stack to flatten the burgers. I don't hit them as hard as they do in the White Manna video because it tends to be a bit messy.
Cover the skillet and let the burgers cook for 2-3 minutes or until a nice charred crust forms on the bottom and the rest of the patty looks light brown rather than pink in color.
Once there is a nice char on the bottom of the patties flip the stack so that the onions end up on the bottom.
Top the burger with both halves of the potato roll. Pour into the pan 3 tablespoons of beef broth (you can use water but the broth adds a little extra flavor) and cover the pan. Cook for another 2-3 minutes until the cheese has melted, and the buns are warmed through and are pillow soft. The liquid helps to not only soften the buns but also melt the cheese.