In a large sauté pan, melt 1 stick of butter over medium heat. Add the breadcrumbs and toast lightly for 2-3 minutes. Remove from heat and stir in the parsley. Season with black pepper, transfer to a mixing bowl and set aside to cool.

Using the same pan, heat the remaining butter over med-high heat. Add the onion, garlic and pancetta and sauté until translucent, about 3 minutes.

Add the mushrooms and sauté for 2-3 minutes. Deglaze* the pan with the wine. (*scrape up the browned bits of food stuck to the bottom of pan)

Add 1/2 tsp of kosher salt and 1/2 tsp pepper. Allow the liquids that develop to evaporate, stirring occasionally. This should take about 5 minutes.

Reduce heat to med-low. Stir the dijon mustard, cream cheese and 1 cup of parmesan cheese into the mushrooms until the cheese has melted. Remove the pan from heat and stir in the herbs.

Pour the filling into a lightly greased baking dish. Add the remaining parmesan cheese to the bowl of, now cooled, breadcrumb topping. Generously top the mushroom filling with the breadcrumbs. Broil under low flame for 4-5 minutes, or until the topping is a deep golden brown.

Remove from the oven and allow to cool for 5 minutes before serving. Enjoy!