01 -
Boil a big pot of salted water, and cook rigatoni following the box's al dente directions. Save 1/2 cup pasta water before draining.
02 -
Toss steak with Cajun spice. Melt 1 tablespoon of butter with olive oil in a big skillet over medium-high heat. Sear meat on all sides for 3-4 minutes until browned. Take it out and set aside.
03 -
Put the skillet back on medium heat, add the other tablespoon of butter, and cook garlic until it smells amazing, about 30 seconds. Pour in the heavy cream and let it softly bubble.
04 -
Reduce heat to low, and bit by bit, stir in Parmesan cheese until fully melted. Add the mozzarella or Fontina cheese if you're using it. Season with more Cajun spice, salt, and pepper to taste.
05 -
Stir cooked rigatoni into the sauce until fully coated. If it feels too thick, add the saved pasta water one spoon at a time until it's just right. Gently add the steak pieces and stir.
06 -
Dish it out right away. Sprinkle extra grated Parmesan and a bit of fresh black pepper on top, if you like.