How to make
Boil the potatoes and mash into a puree together with the grated parmesan. Mix in the baking powder and add some plain flour to get the mixture to dough-like consistency. You can add as little flour as you wish to achieve the consistency that you aim for.
In a pan, sauté the mince, add the chopped mushrooms and 3 tbsp of the tomato puree. Flavour with the oregano, salt and pepper.
Oil your tray and layer half of the potatoes and parmesan mash. Put the cooked mince on top and spread, followed by the rest of the potato dough.
Bake at 390°F (200°C) till the it's nice and golden.
Tuck in!