Place the center-cut bacon in a cold non-stick skillet over medium heat, cooking until the fat renders and the strips are perfectly crispy.
While the bacon cooks, divide the ground beef into two equal portions and form them into small, flat slider patties.
Season both sides of the beef patties evenly with sea salt, black pepper, and garlic powder.
Remove the bacon from the skillet and set aside on a paper towel, then drain most of the fat, leaving just a thin coating in the pan.
Increase the heat to medium-high and sear the beef patties for 3-4 minutes per side until a golden-brown crust forms and they are cooked through.
Top each patty with the sharp cheddar cheese during the last minute of cooking, covering the pan briefly to ensure it melts completely.
Slice the whole wheat buns and lightly toast them in the skillet or a toaster until the edges are golden and warm.
Assemble the sliders by spreading mustard on the bottom buns, then layering the cheesy patties, crispy bacon, tomato, and lettuce.