Deep frying seems like a prefect way to cook a burger. Super high, fast heat transfer to get a crispy, brown crust fast enough to leave the interior nice and medium rare. I looked online for a recipe from America's Test Kitchen or Alton Brown or Serious Eats, but didn't see much. So I thought, "this must be a bad idea for some reason". Yet, there was the oil, ready to go. And I already had the ground beef. So, what the hell.
Of couse I needed cheese , but since I was deep frying I couldn't melt the cheese on the burger, so I stuffed it with some decent aged cheddar that i shaved. I also made the patty pretty flat, since I expected a dramatic shrink when it hit that hot oil. You'll see in the video I was right about that. Aged cheddar also worked out well because both burgers got holes when they shrunk up, and a softer cheese would have leaked, but the cheddar stayed in there. I also made the patties relatively small, about 4-5 oz each I'd guess. After forming them around the shaved cheddar I salted the outside only, because many chef's say mixing salt thoughout the patty causes it to develop a tougher sausage-like consistency instead of the looser ground meat a burger "should" have. Let it sit for a few minute for the salt to absorb and that's it, into the oil. So here's a video of the frying process. Please excuse how dirty my stove top is, I had just cooked a BUNCH of fried chicken. Notice how the burger is fully submerged when I put it in and slowly contracts and sticks out of the oil.
And here's a quick look at the interior after I pulled it out.
And finally, here's the first bite.
As you can see, the exterior has a delicious dark brown crust while almost the entire the interior is a perfect, uniform medium rare. This is much better than the results I've ever gotten with traditional methods of burger cooking. It's similar to a very hot grill, but much easier and the whole cooking process is really fast compared to a pan.
So give it a try. You'll be impressed. And be careful with the hot oil.