Season the chicken breasts generously with salt and pepper, then heat olive oil in a skillet over medium-high heat. Add chicken skin-side down and cook for 6-8 minutes until golden. Flip and cook for an additional 2-3 minutes. Set aside.

In the same skillet, add diced pancetta and cook over medium heat until crispy, about 5 minutes. Remove pancetta and leave drippings in the skillet.

Add sliced mushrooms to the skillet, sauté for 5 minutes, then add minced garlic and shallots, stirring for 1-2 minutes until fragrant.

Sprinkle flour over the vegetables, stirring to form a roux. Gradually pour in the white wine and let it reduce by half, about 2-3 minutes. Stir in chicken stock, heavy cream, and Dijon mustard, bringing to a gentle boil.

Nestle the chicken back in the skillet, spooning the sauce over it. Cover and simmer for 10-15 minutes until cooked through (internal temp 165°F).

Stir in crispy pancetta and parsley before serving, adjusting seasoning with salt and pepper. Serve with sauce generously poured over the chicken.