Mix the spices together in a bowl and store in a jar or air tight container.
Preheat the oven to 180C/375F degrees
Place a piece of Clingfilm on a sturdy chopping board.
Lay a chicken breast on the cutting board with the “top” side down.
Slice into the folds of the chicken breast to open it out. You are almost cutting it in half.
Place another piece of Clingfilm over the chicken breast.
Reach for a rolling pin or mallet and gently pound the chicken until it is about 5cm thick. You could go thinner if you wish.
Repeat for both chicken breasts.
Lay one chicken breast on a piece of Clingfilm and dot a third of the butter over it.
Sprinkle one tablespoon of the Cajun spices over the breast.
Lay the other chicken breast on top and repeat.
Using the edge of the Clingfilm alongside the smallest edge of the chicken (what I would call the bottom edge of the flattened chicken), gently, but firmly roll the chicken like a Swiss Roll.
Smother the remaining butter on the top and sprinkle a tablespoon of Cajun spice over it.
Bake in the oven for 45 minutes, occasionally basting.
Once the chicken is cooked through, remove from the oven and let sit for 10 minutes before carving.
Slice, eat and enjoy!