This is a traditional Bengali samosa filled with paneer and potato curry. It is served with a raita.
Sift the flour and salt into a large mixing bowl. Rub the butter into the flour until the mixture resembles fine breadcrumbs. Stir in the nigella seeds. Add the lukewarm water, little by little, to form a dough, then knead the dough gently for 1 minute. Wrap the dough in cling film and chill it for 30 minutes.
Meanwhile, make the filling. Boil the potato cubes in lightly salted water for 5 minutes, or until just tender. Drain and set aside.
Heat the 1 tablespoon of sunflower oil in a medium pan over a medium heat. Add the chopped onions and fry for 5–6 minutes, until the onions are transparent. Add the sugar and increase the heat to high, frying for a further 2–3 minutes, until the onions are golden.
Add all the spices and the ginger and garlic pastes and fry for 1 minute to cook out the spices, then stir in the chopped tomato. Cook for 3–4 minutes more, until the tomatoes are soft. Add the cooked potato and stir well, mashing the potato slightly, but leaving the mixture chunky.
Stir in the paneer, currants and petits pois, then transfer the filling to a shallow dish. Allow to cool slightly, then place in the fridge to cool completely. When cold, stir in the chopped coriander and peanuts, and season with salt to taste.
While the filling is cooling, make the raita. Put the yoghurt in a small bowl and add the onion, chilli, coriander, mint and cumin, then season with salt to taste. Cover the bowl and put the raita in the fridge to chill.
Heat the oil in a deep-fat fryer to 160°C/315°F. Remove the dough from the fridge and divide it into 12 equal pieces. Roll each piece into a ball. Cover the balls with damp kitchen paper to prevent them drying out.
On a lightly floured surface, roll out 1 of the balls to an oval about 17cm long and 9cm at its widest point. Turn the oval so that a narrow end is closest to you. Use the fine piping nozzle to make 6 holes in the top half of the oval. Brush the bottom with water and fold the top down over the bottom.
Place the folded dough in the palm of your hand with the straight, folded edge nearest your wrist and the punctured side against your skin. Brush the straight edge with water and fold the right corner to meet the left and form a cone. Pinch the open edge to seal.
Divide the filling into 12 equal portions and spoon 1 portion into the cone. Fold the rounded edge down over the filling to create a 3-dimensional pocket and pinch the edges together to seal. Repeat for the remaining dough balls and filling.
Deep fry the samosas in batches of 3 or 4 for 10 minutes each, until crisp and golden. Drain on kitchen paper, then serve with the raita on the side.
Bengali 5-spice is a mixture of equal quantities of cumin seeds, fennel seeds, mustard seeds, oregano, and fenugreek seeds.
For toasted cumin powder, dry fry a few teaspoons of cumin seeds in a nonstick pan over a medium–high heat, tossing the seeds until they begin to smell aromatic (about 3 minutes). Transfer to a spice grinder and grind to a powder.