Cut each chicken breast in half horizontally to form 4 thin steaks total.

Sprinkle both sides with salt and black pepper, then dust lightly with flour, spreading evenly with your fingers.

Melt 1 tbsp butter in a large non-stick skillet over medium-high heat. Add chicken and cook 2 and a half minutes per side until golden brown and just cooked through. Remove from the pan, cover loosely, and keep warm.

Add remaining 2 tbsp butter to the same skillet and raise heat to high. Add mushrooms and cook for 4 minutes until golden on the edges. Do not crowd the pan.

Add garlic plus a pinch of salt and pepper. Cook 1 more minute until garlic is golden and fragrant.

Pour in the white wine. It will bubble and steam. Cook for 30 seconds, scraping all the browned bits from the pan bottom, until the wine is mostly evaporated.

Add chicken stock and cook on high for about 1 minute until mostly reduced. Add cream, reduce heat to medium, and simmer for 2 minutes until the sauce thickens slightly.

Stir in the freshly grated parmesan until fully melted. Taste and adjust salt and pepper.

Return chicken to the pan for 30 seconds to warm through. Garnish with chives and serve from the skillet or plate individually with sauce spooned over the top.