Rinse the potatoes and cut out any large dark spots. Place the potatoes in a large pot and cover with water by 2-inches. Add 1-tablespoon kosher salt and stir well. Bring the water to a boil then reduce the heat to low and simmer just until the potatoes are fork-tender, about 15-20 minutes.
While the potatoes boil, crisp cook and crumble the bacon. At this point, leave the rendered bacon fat in the skillet; set aside.
Drain the potatoes, transfer to a paper towel-lined plate to cool and dry.
While the potatoes cool, adjust the oven rack to lower-middle position and set oven to 425°F. Cover a large, rimmed baking sheet with foil, and lightly spray the foil with nonstick spray. Set the baking sheet in the oven to preheat while the oven heats.
After the baking sheet has heated 10 minutes, add 3 tablespoons rendered bacon fat to the hot pan. Return the pan to the oven so the bacon fat heats.
Once the potatoes have cooled about 10 minutes, use a flat-bottomed cup to smash each potato to about ¼- inch thick – just enough to expose the insides but not enough that the potatoes fall apart.
Once the bacon fat is hot, carefully remove it from the oven and sprinkle it generously with salt and pepper. Place the smashed potatoes in a single layer at least 1-inch apart on the baking sheet. Sprinkle the topside of the potatoes with salt and pepper.
Place the pan with the potatoes in the oven and cook 10-15 minutes or until the underside of the potatoes is crispy and golden brown. Turn each potato over and cook an additional 10-20 minutes or until the other sides is golden brown and crispy.
Transfer the potatoes to a serving plate and top with crispy, crumbled bacon, shredded cheese, sour cream and chives.
Serve immediately.
Enjoy!