Pile the flour onto a clean work surface and make a well in the centre, then add 1 teaspoon of sea salt and 220ml of warm water. Use a fork to bring it together, then knead into a smooth, firm ball of dough. Cover with a slightly damp cloth and rest in the fridge for at least 30 minutes.For the veg filling, prick the potato all over with a fork and cook in the microwave for 10 minutes, or until soft. Defrost the spinach in the microwave, then squeeze out any excess water. Separate the chard leaves from the stalks, then cook the stalks in a pan of boiling salted water for 2 minutes, adding the leaves to wilt for the final 1 minute, then remove from the water and roughly chop on a large board with the spinach and potato (skin and all). Coarsely grate over the Cheddar, add the cottage cheese, mix well and season to perfection with salt and plenty of black pepper.For the meat filling, pound 1 teaspoon each of salt and pepper with the chilli flakes, coriander seeds and fennel seeds in a pestle and mortar, then muddle in 100ml of water. Place the mince in a bowl, peel and coarsely grate in the onion, pour in the spice mixture, then use clean hands to mix everything together to form a loose but mouldable filling.Once the dough has rested, divide into 16 equal-sized balls, then roll each ball out into rough 12cm discs on a flour-dusted surface.Add 1 dollop of filling to the centre of each dough disc. Seal by bringing the dough up around the filling, moving from left to right around the edge, creating at least 12 crimps. Twist the dough at the top, then use scissors to snip the top off.Cook the dumplings in a large pan of salted boiling water for 7 to 8 minutes, or until cooked through, stirring gently for the first 30 seconds. Use a slotted spoon to remove to a platter once cooked. Drizzle with extra virgin olive oil and pick over the soft herb leaves, to serve.