To make spice mix, combine soup mix, black pepper, garlic, onion, parsley and cornstarch in a small bowl. Set aside.

To make stroganoff, heat olive oil in a skillet over high heat.

Add mushrooms and cook, stirring constantly, until mushrooms release most of their juices, about 10 minutes.

Add ground beef, turn heat down to medium and brown until cooked through, about 10 minutes.

Drain the fat off and discard if necessary.

Add noodles and spice mix and stir to combine.

Add milk and beef broth and, bring to a boil.

Reduce heat and simmer, stirring occasionally, for about 20 minutes, or until liquid is absorbed.

Add more broth, if needed.

Remove from the heat and stir in sour cream.

Taste and adjust seasoning. Top with grated cheese and serve immediately.