Preheat oven to 400º Fahrenheit. Line a baking sheet with parchment paper.
Heat 1 tablespoon butter and 1 tablespoon olive oil in a large saucepan over medium-high heat. Add chopped mushrooms and sauté without stirring about 3 minutes. Season mushrooms with salt and pepper, and continue to cook until both sides are golden brown, about 3 minutes. Add half of the garlic to the pan with the chopped mushrooms and quickly sauté 20-30 seconds (making sure they do not burn). Using a slotted spoon, transfer mushrooms to a medium bowl; allow to cool.
In the same bowl with the mushrooms and garlic, add ground chicken, breadcrumbs, parmesan, egg, fresh parsley, 2 teaspoons kosher salt and black pepper; mix everything together until just combined. Roll into small meatballs (should yield about 25-30 meatballs) and place in prepared baking sheet. Transfer to oven and bake for about 15 minutes or until meatballs are cooked through.
Meanwhile, using the same pan used to cook the chopped mushrooms and garlic, heat remaining butter and olive oil on medium-high heat. Add the sliced mushrooms and sauté without stirring about 3 minutes. Season mushrooms with salt and pepper, and continue to cook until both sides are golden brown, about 3 minutes. Add the shallots, and cook for 1 to 2 minutes more, add the remaining garlic and quickly sauté 20-30 seconds. Pour the Marsala wine in the pan and boil down for a few seconds to reduce some of the alcohol. Add the chicken stock and cream and simmer until sauce is reduced – about 3-5 minutes. Add meatballs to skillet, cover and reduce heat to low and simmer for 10 minutes. Garnish with fresh chopped parsley. Serve with mashed potatoes or pasta. Enjoy!
