Pre-heat oven to 200°C
In a mixing bowl, add the Cajun spice mix, lemon juice and garlic and mix well.
Flatten out a sheet of foil and place the asparagus, cherry tomatoes and spring onion in the middle of the sheet. Season with salt and black pepper.
Spread the Cajun spice mix evenly over each of the cod fillets.
Place the cod fillets on top of the vegetables. Add 1 tbsp of water and top with the other piece of tin foil. Roll each of the sides up around the vegetables and cod to make a parcel.
Put the parcel onto a baking tray, place into the oven and cook for 15-20 minutes until the fish is cooked.
Serve with the lemon wedges and accompaniment of your choice.