Step 1

At least an hour prior to cooking, start by finely slicing the onion, and placing slices in a bowl. Sprinkle with 2 tsp salt and allow to sit, mixing occasionally for about an hour. This will help draw out excess moisture and help the onions to brown faster. You need to make sure your slices are thin, because the onions are only going to have a few minutes to cook, and if they’re too chunky they may remain raw in the middle.

Step 2

Line a tray with greaseproof paper. Divide the meat into 10 portions, loosely forming each portion into a ball, then place onto the lined tray. These can go back into the fridge until about 10-15 minutes before you are ready to use them.

Step 3

Light your grill and place the flat griddle on top, allowing it to heat to a high temperature.

Step 4

Place onions in a dishcloth (paper towel will fall apart too easily) and wring them until you’ve removed the bulk of the moisture. Now, you’re ready!

Step 5

Spray the hot griddle with a little oil, and place smalls handful of onions in little stacks, allowing yourself enough room to flip the burgers. I was able to do 5-6 per batch.

Step 6

After about 3-4 minutes of browning, place a ball of beef on top of each stack and using your turner, slowly but firmly press the ball down onto the onions to form a patty that should be less than 1/2 inch thick. You may need to press them a second time to reach the desired thickness. Repeat until all onion stacks now have a smashed patty on top, and allow to cook a further 2-3 minutes.

Step 7

Using your turner, get a good solid scrape and flip the burgers to cook the other side. The majority of the onions should have adhered to the beef. Allow to cook on the other side 2-3 minutes. If you prefer your cheese to be meltier, layer it on top of each patty as soon as they are flipped. Otherwise, wait until 30 seconds before you take them off the griddle.

Step 8

Halve the buns in preparation for stacking, and have them on a tray nearby. Remove the burgers from the grill and stack onto the waiting bun bases. Put the bun top in place, eat and enjoy!