For the Mash. Wash the potatoes very well, prick the skin with a fork, arrange into a glass bowl with a splash of water and microwave for 20 minutes at 800W. Allow to rest for 10 minutes without opening the microwave door (see notes for alternative cooking methods).
Remove the potatoes from the microwave, and carefully peel the skin off while they're still warm.
Season with salt, pepper and nutmeg, then mash until smooth. Set aside to cool completely.
Turmeric cheesy sauce. In a pan combine tapioca, nutritional yeast, turmeric, salt, onion and garlic powder. Add the plant-based milk a bit at the time and stir well with a whisk to avoid forming lumps. Heat the sauce on the stove until it thickens (3-4 minutes) stirring with a spatula all the time.
Sautéed Courgettes. Finely chop the garlic and slice the courgettes to a 3 mm thick slices. Add to a pan with olive oil and sauté until cooked thoroughly (around 20 minutes). Turn off the heat, add some chopped mint, give it a last stir and allow to cool.
Once cool, combine the courgettes with around ¼ of the turmeric cheesy sauce (or to taste). See notes on how to use leftover turmeric sauce.
Assembling. Divide the mash potato into 8. Roll each portion into balls, then flat the potato mixture with the palm of your hands onto a sheet of baking paper.
Scoop the turmeric and courgette filling onto 4 discs. Carefully, place the other disc on top of the base and filling, and seal well the edges.
Heat ½ inch of vegetable oil into a pan. Fry the potato cakes on each side for 4-5 minutes until golden.
Transfer the potato cakes on a plate with kitchen paper to absorb the excess of oil.
Serve immediately for oozy filling.