Slice your chicken breasts in half and set aside. Wash and slice your mushrooms and set aside. Mince garlic and assemble remaining ingredients.
Heat a large, rimmed skillet over medium heat. When hot add in a tablespoon each of oil and butter. When butter is melted, add in your mushrooms with a ¼ tsp of salt. Let caramelize, stirring occasionally, about 3 to 4 minutes.
Season your sliced chicken with 1 tsp of salt and a ½ tsp of pepper.
Once golden, remove mushrooms to a bowl. Turn heat to medium high and add another tablespoon each of oil and butter.
When the butter is melted, add chicken to the pan and sear on each side, until golden brown. About 3-4 minutes per side.
Remove chicken and turn heat to low. Add garlic and stir until fragrant, about 30 seconds.
Slowly pour in Marsala wine, scraping the brown bits from the bottom of the pan. When all the wine is added, add the chicken stock and bring to a simmer over medium heat. Once bubbling, let cook for 2 to 3 minutes.
Slowly, while stirring, add in the heavy cream and final tablespoon of butter until completely combined. Taste and adjust salt if desired.
Whisk together two teaspoons of cornstarch with one teaspoon of cool water until smooth. Slowly add the slurry into the pan while stirring.
When sauce is thickening, return mushrooms and chicken to the pan, coating them with sauce and mushrooms until everything is hot.
Serve immediately with a generous serving of sauce.
If you've tried this recipe, come back and let us know how it was!