Boil a large pot of salted water and cook the rigatoni until al dente, about 10-12 minutes. Drain and set aside.

Heat olive oil in a skillet over medium-high heat, add steak, and sear for 3-4 minutes until browned. Remove and let rest.

In the same skillet, sauté the diced onion and bell pepper until softened, about 5 minutes. Add minced garlic and cook for another minute.

Lower heat, add heavy cream, and scrape up bits from the pan. Stir in blue cheese, oregano, salt, and pepper until the sauce is creamy.

Return seared steak to the skillet and toss to coat. Fold in the cooked rigatoni until well combined.

Preheat oven to 375°F (190°C). Grease a baking dish, pour in the steak and pasta mixture, and top with mozzarella.

Bake for 15-20 minutes until cheese is bubbly and golden. Keep an eye on it to prevent overcooking.

Let cool for a few minutes, garnish with parsley, and serve warm.