Sweat the chopped garlic clove in a pan and then mix the spinach and processed cheese together in the pan.
Preheat the oven to 180 degrees circulating air.
Season the chicken fillets with salt and pepper and place in the baking dish. Season the spinach and cheese mixture with salt and pepper and pour over the fillets. Sprinkle the parmesan on top and put the casserole in the oven for 25-30 minutes.