Finely slice the onions and dice the pancetta
In a large pan, cook pancetta over medium heat for 5 minutes
Add onions and cook for about 10 minutes, until soft
Add a few cubes of butter and the chopped herbs
Deglaze with white wine and simmer for 2 more minutes
Thinly slice the potatoes using a mandoline and trim each slice into uniform circles
Slice or cube the soft cheese
Grease an 11-inch pan with butter
Layer the potato slices tightly together and season with salt and pepper
Add some of the onion-pancetta mixture, soft cheese, a sprinkle of Parmigiano, and a drizzle of cream
Repeat layering at least 3 times
Shape the top layer neatly, season and sprinkle with remaining Parmigiano
Cover with parchment paper and then foil
Bake at 360°F for 1 hour covered
Remove covers and bake at 430°F for 30 minutes until golden and crisp on top
Let the gratin rest for 10-20 minutes before serving
