1Preheat your oven to 220.
2While the oven is heating up, prep your veggies. Begin by coring the iceberg lettuce, simply cut around the core using a small serrated knife and pull it out with your hands. Remove two lettuce leaves, stack them, cut out a square the size of your burger bun and set aside. Next, peel a red onion, leaving it whole, and slice a couple of rings at a thickness of your liking and set those aside, too.
3By now your oven should have come up to temperature. Spread the chips evenly on an oven tray and pop them in for 15-20 minutes, giving them a quick check and a toss once or twice as they cook.
4Prep your spicy mayo by mixing the mayo and hot sauce in a small bowl and set aside.
5Slice your buns in half and spread with butter. Bring a skillet up to medium-high heat and place your buttered buns face-down for a couple of minutes until crispy and golden brown. Remove the buns and add cooking oil to the hot skillet. Grab a flat-bottomed glass or flat spatula and oil the side you’re going to use for smashing the burger to prevent it from sticking.
6Place your burger patties in the skillet, season them with salt and pepper, and immediately smash them down using your flat-bottomed tool of choice. Sear for 2 minutes on the first side, then flip them over. Immediately add a slice of cheese to each pattie and as many jalapeños as you can handle. Cover with a lid and cook for a further 2 minutes.
7Quickly move on to building your burger—I do bun, spicy mayo, lettuce, the two cheesy patties, and red onion rings, then top it all off with the other half of the bun that I'd smeared in more mayo. Serve with hot chips on the side, and enjoy.