• 2 large potatoes, peeled
• 2 large carrots, finely chopped
• 2 tbsp vegetable oil, plus extra for deep-frying
• 1 small onion, finely chopped
• ½ tsp turmeric
• 2 tsp garam masala
• 1 tsp black mustard seeds
• 1 tsp salt
• ½ tsp freshly ground black pepper
• 4 garlic cloves, finely chopped
• 1 green chilli, seeds removed, finely chopped
• 10 curry leaves, finely chopped
• 75g/3oz frozen peas, defrosted
• 1 tsp lemon juice
• handful fresh coriander leaves

Method

For the pastry, mix the flour and salt together in a bowl then pour in the oil and egg yolk and mix together until the mixture resembles breadcrumbs. Gradually stir in enough warm water to form a smooth dough (you may not need all the water). Roll the dough into a ball, wrap in cling film and chill in the fridge for least half an hour

For the filling, boil the potatoes in a saucepan of salted water for 15-20 minutes, or until just tender, then drain. When cool enough to handle cut into 0.5cm/¼in cubes and set aside. Boil the carrots in a saucepan of salted water for 10-12 minutes, or until tender, then drain. Set aside.

Heat the two tablespoons of vegetable oil in a large frying pan over a medium heat then add the onion, turmeric, garam masala, mustard seeds, salt and black pepper and fry for about 8 minutes until the onions are softened and translucent and the spices aromatic. 

Stir in the garlic, chilli, curry leaves, potato and carrot and cook for a further ten minutes then stir in the peas and cook for 2-3 minutes until heated through. Season with the lemon juice, stir in the coriander leaves and set aside to cool.

To make the samosas, cut the dough into six even-sized pieces and roll into balls. Use a rolling pin to roll each ball into a thin circle, about 15cm/6in diameter. Cut each circle in half to form two semicircles.Take a semicircle and fold into a cone, brushing the edges with the reserved egg white to seal. Fill the cone about half-full with the samosa filling then brush the top edges with egg white and press tightly to seal. Repeat with the remaining dough and filling.

To cook the samosas half-fill a deep, heavy-based pan with vegetable oil and heat until a cube of bread dropped in sizzles and turns golden-brown in 30 seconds (CAUTION: hot oil can be dangerous. Do not leave unattended). Fry the samosas in small batches for 4-5 minutes, or until golden-brown and crisp. Remove from the oil with a slotted spoon and drain on kitchen paper. Serve.