Cook the penne according to package directions for al dente. Drain and set aside.
Season the steak on both sides with ¾ tablespoon blackened seasoning. In a medium bowl, toss the shrimp with ½ tablespoon blackened seasoning.
Heat 1 tablespoon olive oil in a large skillet over medium-high heat. Sear the steak 3-4 minutes per side, until it reaches an internal temperature of 135 °F- 140 °F. Cooking time will vary with the size of the steak. Remove from the skillet, let steak rest for 5 minutes, then slice into bite-sized pieces.
Add the remaining 1 tablespoon olive oil and lower the heat to medium. Cook the shrimp about 2 minutes per side. Remove and set aside.
Add the butter to the pan. Once melted, add the onion and garlic and cook 2–3 minutes, until the onion begins to turn translucent.
Stir in ½ tablespoon blackened seasoning and ½ teaspoon salt. Add the flour and cook 1 minute, stirring.
Add the heavy cream, chicken broth and chicken bouillon powder. Cook a few minutes, until the sauce begins to bubble lightly.
Lower the heat to low, add the Parmesan and stir until the sauce has thickened.
Add the steak, shrimp and cooked pasta and stir everything together. Serve with fresh Parmesan.
Notes
Check that your blackened seasoning, broth and bouillon are gluten free. Swap ribeye for sirloin or New York strip if you like.Storage: Store leftovers in an airtight container in the fridge for up to 3 days.Reheating: Reheat gently on the stovetop over low heat with a splash of milk or broth to loosen the sauce. Cream sauces can separate in the microwave, and the shrimp can overcook.Freezing: Cream sauces and shrimp don't freeze well, so this one is best enjoyed fresh.