For 1 portion take a tennis size ball of beef mince. Take a griddle pan and heat it, than, add some olive oil. Then, season your mince with salt and pepper and add 1 egg yolk. Then, add just a little bit of finely chopped chilli. Give all that a good mix.
Form a meat ball and, then, flatten it and inch in height.
Slice a half of an onion nice and thick. Season it with salt and add a touch of olive oil. Next, place your onion on the grill, along with 4 stripes of bacon.
When bacon and onion are nicely colored on both sides in about 4 minutes, remove them from the grill. Add 10 g of butter on the grill. Turn the burger on another side, put 1 slice of cheddar and cover with tin foil. Cook for more 6 minutes.
Take a bun, slice it to make 2 equal parts and place on the grill. Cook the bun until crispy and golden.
For the sauce, take 2 tablespoons of mayonnaise, season it with salt and pepper. Then, add ½ teaspoon of Sriracha. Mix that up.
Take a base of a bun and spread some sauce. Then, place a leaf of a gem lettuce, 3 slices of tomato. Place grilled onions over tomato, then, place the burger, and, finally add your crispy bacon. Cover with second half of a bun.