Peel and cut both types of potato into small dice. Place in a pan of cold salted water and bring to the boil. Once soft and tender, drain the potatoes and then place in a food processor with half the butter and a pinch of salt and pepper. Blend until smooth and keep warm until ready to serve.
Preheat the oven to 200'C.
Pick the sage leaves from the stalks. Cut the mozzarella into slices. Cut the slices of parma ham in half.
Cut each chicken breast into 4 pieces by cutting across the width of the breast. Place each piece of chicken in between two pieces of cling film and flatten gently with a rolling pin until you have 5mm thick discs. Season with salt and pepper and then place 1 or 2 leaves on top of each disc of chicken. Add a slice of mozzarella and a piece of ham.
Heat a frying pan over a medium heat and add a splash of oil. Dip each chicken disc in the flour and then place in the pan and cook for 4 minutes. Transfer to a baking tray, place in the oven and cook for a further 6 minutes.
Add the madeira to the frying pan used to cook the chicken. Allow the madeira to reduce by half before adding the stock. Reduce by half again and then remove from the heat.
When you have your sauce reduced, pour it into a jug for serving, add the remaining butter to the pan and add the spinach, cook for a minute and remove. Strain well before serving.
To serve: Spoon the sweet potatoe mash onto the plate, top with the spinach and then the saltimbocca disks, pour your sauce over and serve.
«Replace the chicken with veal for a classic saltimbocca or altenatively try using red mullet.»