Place the puff pastry slices next to each other and defrost. Clean and wash the spinach and blanch in bubbling salt water for 2 minutes. Rinse in cold water and drain on a sieve.
Squeeze the spinach well. Melt the fat in a pot. Stir in flour, add milk and vegetable stock and bring to the boil while stirring. Grate parmesan, add to the sauce and season with salt, pepper and nutmeg.
Clean and slice the mushrooms. Peel onion and garlic and chop finely. Heat olive oil in a pan. Sauté the mushrooms in it. Add the diced garlic and onion and fry for about 2 minutes.
Cut Cabanossi diagonally into slices. Grease the moulds ( cm Ø) and sprinkle with flour. Roll out the puff pastry and cut out in a circle ( cm Ø). Place the dough in the moulds and prick several times with a fork.
Add the spinach and mushroom-onion mixture to the sauce. Pour the mixture into the moulds. Put cabanoshi slices in the filling in a star shape. Coarsely grate the Gouda and sprinkle over the filling. Bake the spinach and puff pastry pans in a preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas mark: 3) for about 20 minutes.
Serve immediately.