Rub the cajun spice into the chicken breasts and set aside
Heat 2 tablespoon of butter with a drop of olive oil (to prevent burning) in a large pan. Cook the chicken on both sides for about 4 minutes per side. If breasts are thicker you may need a minute longer. Cover with foil and set aside
Add the other 1 tablespoon of butter to the excess butter from the chicken and add the garlic and sauté for a minute
Add the mushroom and cook until brown
Remove the mushrooms and set aside
Add the tablespoon of flour to the same pan and whisk for a minute until it thickens
Add the chicken broth, cream and parmesan cheese and simmer further until it thickens
Add the Chicken, mushroom and spinach back to the sauce and turn off the heat
Season with pepper and more salt if required
Garnish with some parsley and serve over mash potatoes or pasta