Cook the fettucine according to the package instructions, then drain and set aside.
Sprinkle the steak and shrimp with 1 teaspoon each of the Cajun seasoning, along with a pinch of salt and pepper. Toss to coat.
Heat the butter and olive oil in a large cast-iron skillet over medium-high heat. When the butter has melted and the oil is hot, add the steak and shrimp and cook until the steak has browned on all sides and the shrimp are opaque and almost cooked through, about 3 minutes. Remove the steak and shrimp to a plate with a slotted spoon.
Add the bell peppers and onion to the same skillet, then sprinkle over the remaining teaspoon Cajun seasoning. Cook until the veggies begin to blacken, 1 to 2 minutes. Add the tomatoes and garlic, then stir gently for an additional 30 seconds. Add the chicken stock and wine, stirring to release all the flavors from the bottom of the skillet. Allow to cook for a couple minutes, then reduce the heat slightly. Add the cream, Worcestershire sauce and hot sauce, then continue to cook until the sauce has started to thicken. Taste and adjust the seasonings as needed.
Add the steak and shrimp back to the skillet along with any juices left on the plate, then stir. Add the fettuccine and toss to combine.
Garnish the skillet with the scallions and parsley, then serve and enjoy.