Preheat your Blackstone Griddle to medium-high heat, pour a little avocado oil on the griddle surface and smear around the flat top to get a fresh coat of oil while it heats up.

Assemble all of the ingredients, herbed mayo should be prepared first and allowed to chill in the refrigerator while cooking.

To make the herb mayonnaise chop the scallions and fresh parsley, and press the garlic through a garlic press. Add to a small bowl.

Combine the mayonnaise with these fresh herbs and add lemon juice and the optional white truffle oil (it’s not necessary but a fun addition to this herb mayonnaise recipe). Season with salt and pepper and place in the refrigerator to chill.

To make caramelized onions on the Blackstone Griddle, slice the onion, on a cutting board slice off the root and the tip of the onion. Balance it on one of these flat sides and slice it down the middle. Now take each side of the onion and slice from root to tip into thin ¼ inch ribbons. Place these slices into a bowl.

Melt 4 tablespoons of butter in the middle of the Blackstone Griddle and add the sliced onions onto the cooking surface. The burners should be on medium high heat.

Sprinkle the onions with the steakhouse seasoning or any seasoning salt that you like. Toss well in the butter. Cook for 15 minutes, tossing every once in a while with your spatula. I move the onions to the back while cooking the burgers so that they can continue to caramelize and develop rich flavors.

To slice the jalapenos, first cut off the stem. Then slice them in half down the middle. Line them up and slice them again into half-moons. I left the ribs and seeds in for spice but ribs and seeds can be removed BEFORE slicing if you prefer a milder burger. Or simply leave the jalapenos out if you like.

Melt 4 tablespoons of butter on an area of the griddle. Add your sliced jalapenos to the butter and toss well in the butter. Season with the steakhouse seasoning, or any seasoning salt you like. Cook 5-10 minutes over medium heat, tossing occasionally. Move to the front of the griddle, or off to the side while you sear the burgers.

For the burger patties, I used 4 pre-made burger patties. You can form your own burger patties using hamburger meat with your hands or with a burger press like this one.

Season the raw patties well on the outside with steakhouse seasoning or any seasoning salt you like. My steakhouse seasoning contains salt, pepper, garlic powder, and onion powder. I use about a teaspoon on each side of each burger. You can also sprinkle each of these spices on separately if you like, don’t overthink it.

On the freshly greased Blackstone, place the burger patties down onto the middle of the griddle, which I find to be the hottest area.

You can use the high-temperature oil or butter to grease the griddle lightly, just make sure it is nice and slick. Place the patty down and smash with a large spatula into a thin patty. I close my griddle and let this side cook for 4-5 minutes. If you don’t have a lid on your Blackstone, simply use a disposable aluminum pan placed over the meat to help it cook.

After 5 minutes, flip the burgers. Cook an additional 2-3 minutes. Top with one slice of cheese and place the lid back down to help the cheese melt.

Last, place the buttered buns down on the griddle surface to toast them lightly. This only takes about 1 minute. Remove and place each toasted bun on a plate. Slather with the herb mayonnaise.

Top each cheesy burger patty with caramelized onions and jalapenos if desired. Place on top of each bun. Top with the other half of the hamburger bun. Congratulations you've made the best burger on the internet! Serve immediately.