Cook pasta shells in salted water until al dente. Drain and set aside.

Melt butter in saucepan, whisk in flour, then slowly add milk and cream. Simmer until thick.

Stir in Parmesan, nutmeg, salt, and pepper. Toss pasta with sauce.

Heat skillet with olive oil. Sear steak bites until browned.

Add butter and garlic to steak, toss to coat.

Serve steak bites over creamy Parmesan shells and garnish with parsley.