Fried Onion Double Smash Burgers

I have wanted to make a smash burger for a long, long time.  My first attempt failed because I absently used 4 ounce patties instead of 2.  They were too big and wouldn't smash.  Today was try 2!  I love potato buns so that is what I served on.  I saw the recipe on a cooking show so thought I'd use it though there are many on the web...

• 1 large onion, halved and sliced as thinly as possible
• Kosher salt and fresh cracked pepper, to taste
• 1 tablespoon grapeseed oil
• 1 lb grass-fed lean ground beef, portioned into 8 balls 
• 4 slices cheese, I used 2 processed and 2 jalapeno/Monterey Jack

I used my "Lodge" cast iron griddle for this.  I sliced the onion as thinly as possible and put it in a colander.  I salted with 1 tablespoon of kosher salt, tossed and let sit for 20 minutes.  I patted dry on paper towels and then mixed them with the oil in a bowl.

I heated the griddle on med-high heat until ready to smoke.  I divided the onion into 8 even piles and then seasoned with pepper. 

I cut the beef into 8 equal sections and rolled them into balls.  

This would make 4 double burgers.  

I put a beef ball in the middle of each pile and used a strong spatula to smash it down.  It is NOT easy and even though I thought I had the perfect spatula, I could not get them as thin as they should have been.  I seasoned with S&P.  I let these sit until onions looked nice and brown.  

I flipped each pile with the onions and then put the cheese on top of patty.  Then I put the buns cut side down over the patties .  

When buns were steamed I took the bottom buns with matching cheese burgers and flipped them over onto a plate.  I put the second matching cheese patties with top bun on top of the first ones.  These were too small for the bun though it worked if you pushed one patty off to the side.

So, this is my second attempt making these.  I won't do it again, I'll leave it to the burger pros out there for them.  Both times were good though both times were not true "smash" burgers.  Below was my first attempt when the patties were too large.  

These are a lot of work for little gain since I can't seem to do it right, including the heat for cooking them.  Twice was enough.  I'll be googling where the best smash burger is in town next time I want one...  Hmmm, I can buy a smash burger shmusher...something to consider... 🤔