Mix olive oil and Cajun spices in a bowl and add the shrimp, mixing until they are nicely covered with spiced olive oil. Set them aside.
Mix the chicken pieces with olive oil and Cajun spices and set them aside, and let them marinate while preparing the rest of the ingredients.
Put some water to boil for pasta before starting the sauce.
To make the sauce, place a large pan or wok on medium heat and melt the butter.
When the butter starts sizzling, add the shrimp and cook for a minute, until they turn pink and start to curl. Don't be tempted to cook any longer, as they will cook more later with the sauce.
Remove the prawns to a plate and set them aside to use later.
Using the same pan, sauté the chicken pieces for five minutes or until they are thoroughly cooked, and place them on the same plate with the shrimp. The cooking time varies depending on the size of the chicken pieces.
Add the garlic to the same pan and quickly sauté for 30 seconds with the remaining butter and then add the peppers.
Sauté peppers for another minute and then add the tomatoes (and chilies if using).
Cook the tomatoes until soft, for about a couple of minutes, and then add the double cream, salt, and pepper.
The water for the pasta should be boiling at this point. Add plenty of salt to boiling water and add your pasta in. (Assuming that you are using dried pasta which usually takes 10 to 12 minutes. If you are using fresh pasta, start cooking it later).
Reduce the cream down for a few minutes and then add the blue cheese (optional) along with the lemon juice.
Cook for a few more minutes, stirring until the blue cheese(if using) melts into the creamy sauce before adding the cooked pasta.
Add the rest of the cheese, chopped herbs, chicken, and shrimp last minute.
Stir all well together until nicely combined and then remove the pan from the heat.
Serve with some more grated cheese and chopped herbs.