Step 1
Place an oven rack in the bottom third of the oven and preheat oven to 450 degrees F (230 degrees C).
Step 2
Place potatoes in a large pot and cover with cold water and salt. Bring to a boil; reduce heat to medium and simmer until potatoes are just tender when pierced with a fork about 12 minutes. Drain.
Step 3
Return potatoes to the pot; cover with a lid and shake pot vigorously about 1 minute. Uncover and cool potatoes until easily handled about 10 minutes. Peel potatoes and cut them crosswise into chunks.
Step 4
Place bacon in a skillet and cook over medium-high heat turning occasionally until most of the fat has melted and bacon is tender 5 to 7 minutes. Drain bacon slices on paper towels reserving bacon fat in the skillet.
Step 5
Brush the bottom of a shallow 10x15-inch baking pan with half of the bacon fat and olive oil. Sprinkle salt and pepper over potatoes and arrange in the baking pan.
Step 6
Roast potatoes in the preheated oven until golden brown on the bottom about 30 minutes. Remove potatoes from oven and reduce oven temperature to 375 degrees F (190 degrees C).
Step 7
Turn potatoes over in baking pan. Top with bacon pieces Parmigiano-Reggiano cheese and garlic. Drizzle remaining bacon fat on top.
Step 8
Return to the preheated oven and continue roasting until Parmigiano-Reggiano cheese is melted about 15 minutes. Sprinkle with parsley and serve.