Divide the ground beef into four 1/3 pound burgers. With a light hand, shape into patties. Season both sides with a salt, pepper and garlic powder. Set aside until ready to grill. May, also, be pan fried.
Heat grill (or pan) to medium - medium-high heat and grill for a 4-7 minutes on each side until desired doneness. During the last minute of cooking , add a slice of cheese over each burger and close cover until cheese begins to melt. While the burgers are cooking, add the onion slices and allow them to char a bit on each side and begin to soften. Remove burger and onions from grill and allow to rest for 2-3 minutes before serving.
Place a burger on each toasted bun bottom, topping with 2 slices of bacon and 4-5 jalapeno slices. Slather some of the chipotle mayo on the top bun and place a grilled onion round on top. Add lettuce, if so desired, and top with the top half of the bun.