Preheat oven to 350°F and cook meatballs according to the package instructions and set aside for later use.
To make the sauce, set a large sauté pan over medium heat, add the butter and the mushrooms. Cook for 5 minutes until the mushrooms begin to brown, stirring often.
Stir in the kale, shallots and garlic and cook for an additional 5 minutes. Sprinkle in the flour and stir well. Add the chicken stock and bring to a boil. Add the cooked meatballs to the sauce and reduce to a simmer. Season the sauce with salt and black pepper to taste.
Bring a large pot of water to a boil and cook the orecchiette according to the package instructions. Drain and return to the pasta pot.
To serve, divide the pasta among bowls, top with meatballs and sauce, and garnish with parmesan cheese.
