4 (6-8oz) chicken breasts, boneless skinless,
tenderloins removed and trimmed
1 C flour
1/4 C vegetable oil
2 1/2 oz pancetta, cut into pieces 1 inch long and 1/8 inch wide or bacon
8 oz white mushrooms, trimmed & sliced thin
1 garlic clove, minced
1 tsp tomato paste
1 1/2 C sweet Marsala wine
4 1/2 tsp lemon juice
4 T unsalted butter, cut into 4 pieces and chilled
2 T chopped fresh parsley
Halve chicken horizontally, then cover chicken halves with plastic wrap and pound to an even 1/4 inch thickness with meat pounder. Place flour in a shallow dish or pie plate. Pat chicken dry with paper towels & season with S&P. Working with 1 cutlet at a time, dredge in four mixture, shaking off excess, and transfer to large plate. Heat 2 T oil in a 12 inch skillet over medium-high heat until shimmering. Place 4 cutlets in skillet and cook until golden brown on first side, about 3 minutes. Flip cutlets, reduce heat to medium, and cook until no longer pink and lightly browned on second side, about 2 minutes longer; transfer to large oven safe plate. Wipe out skillet. Repeat. Tent w/foil & keep warm in 200 degree oven.
Cook pancetta or bacon in now-empty skillet over low heat, stirring occasionally and scraping up any browned bits, until crisp, about 5 minutes. Remove pancetta with slotted spoon and transfer to paper towel lined plate. Add mushrooms to skillet, increase heat to medium-high and cook stirring occasionally, until softened and lightly browned, about 8 minutes. Stir in garlic and tomato paste, and cook until tomato paste begins to brown, about 1 minute, stir in Marsala, return to high heat, bring to a vigorous simmer, and cook stirring occasionally, until sauce is thickened.
Turn off heat, stir in lemon juice. Whisk in butter, 1 piece at a time. Stir in parsley & crispy pancetta, or bacon, season with S&P to taste. Pour sauce over chicken and serve immediately.