Preheat broiler on the oven.
In a bowl, combine chuck, chili powder, cumin, paprika, 1/8 tsp garlic powder, oregano, and cayenne (optional). Now form the chuck into 4 paddies that is large enough to fit nicely onto the bun. Season the outside of the paddies with salt and pepper.
While the burgers are marinating, in a small bowl combine mayonnaise, chopped jalapenos and ¼ tsp garlic powder. Set aside for later.
In a large pan heat the oil over medium-high heat. When oil is hot add the hamburgers to the pan. Press down firmly and let brown on each side for about 5 minutes. Cook to preferred doneness.
Remove the burger from the pan and then add the onion slices. Brown heavily on both sides of the onion until caramelized and tender.
Now remove the onions from the pan. Add back the hamburgers and cover them with the shredded cheese. Place in broiler and melt cheese.
To assemble. Smear a healthy amount of jalapeno-mayo on bottom of the bun, now add the shredded lettuce and top with the burger paddy. Pop the middle out of the onion slice and place on top of the burger. In the middle of the onion add Cal & Gary’s Salsa and top with the onion middles and cilantro leaves. Place the lid of the bun on top and enjoy!