Clean the potatoes and place them in a large pan. Add cold water about 2 inches above the potatoes and pour in 2 tsp coarse salt.
Boil the potatoes until fork tender, about 15-20 minutes.
While the potatoes are boiling, prepare the onions and pancetta.
Slice the onion and, if necessary, the pancetta.
Add 1 tbsp olive oil to a large skillet and heat over medium-high heat.
Place the sliced onions in the skillet and cook, stirring occasionally, until translucent, lightly brown, and very soft, about 15 minutes. You may need to lower the temperature a bit to avoid browning the onions too quickly.
Remove the onions and add the pancetta to the pan. Cook until crisp, about 4 minutes.
Drain the cooked potatoes and give them a rough chop.
Return the onions to the pan with the pancetta.
Add the chopped potatoes to the pan and cook all together until the potatoes are browned, about 5-8 minutes.
Lightly salt and pepper (remember that pancetta is a bit salty).
Evenly sprinkle the cheese over the potatoes, onion, and pancetta and cook over medium heat until the cheese is melted, about 3 minutes.