Heat a large, oven safe skillet on the stove over medium heat. Add a tablespoon of olive oil, onion and mushrooms. Cook, stirring often, until vegetables have softened; about 4-5 minutes. Add garlic and stir and cook one minute more. Transfer vegetables and garlic to a plate.
Add ground beef to the skillet and season with a bit of salt and pepper. Cook, breaking up large chunks with a spatula or wooden spoon, until meat is no longer pink. Drain any excess grease from the pan. Remove pan from heat. About 6-7 minutes.
Return onions, mushrooms and garlic to the skillet and stir to combine. In a separate bowl, stir together tomato soup and sour cream, then add that to the skillet along with 1 cup of the grated Mozzarella and cooked pasta. Top with remaining shredded Mozzarella.
Bake in preheated oven for about 20 minutes, or until top is golden and sauce is bubbly.
Let stand for 5 minutes, then garnish with fresh minced parsley.
Feel free to add frozen veggies to the mix or use ground turkey in place of ground beef.