Cut the bacon into small cubes and leave them crisp in a pan without fat. Clean, wash and drain the spinach. Peel garlic and onion and dice finely. Heat 2 tablespoons of oil in a large pot.
Fry the garlic and onion in it. Add the spinach, except for something to garnish, and let it collapse. Take out, let cool slightly and squeeze out. Add bacon. Season to taste with salt, pepper and nutmeg.
Peel, wash and chop the potatoes. Cook potatoes in salted water for about 20 minutes until soft. Wash the meat, dab dry and cut a pocket into each. Fill the pockets with spinach and pin them up with wooden skewers.
Season fillets with salt and pepper. Heat 3 tablespoons of oil in an ovenproof pan and fry the fillets on both sides. Then finish cooking in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 12 minutes.
Drain tomatoes and capers well. Cut the tomatoes into pieces. Heat milk and butter in a small pot. Drain the potatoes, let them evaporate, mash them finely and mix with the milk.
Add the tomatoes and capers. Remove meat from the oven and cut into slices. Arrange mashed potatoes and meat on plates. Garnish with remaining spinach and sprinkle with chilli.