In a large mixing bowl, combine 2 cups flour and 1/2 teaspoon salt. Make a well in the center and add 4 tablespoons oil. Rub the oil into the flour using your fingertips until the mixture resembles coarse breadcrumbs.

Gradually add warm water, 1-2 tablespoons at a time, mixing with your hands until a firm dough forms. The dough should be slightly stiffer than bread dough and not sticky. Knead for 3-4 minutes until smooth.

Cover the dough with a damp kitchen towel and let it rest for 30 minutes. This resting time is crucial for developing gluten and achieving the perfect flaky texture.

Heat 2 tablespoons oil in a large skillet over medium heat. Add cumin seeds and crushed coriander seeds, frying until fragrant, about 30 seconds.

Add minced ginger and garlic, cooking for 1 minute until aromatic. Add turmeric, garam masala, and red chili powder, stirring constantly for 30 seconds to prevent burning.

Add diced potatoes and peas to the pan. Season with salt and mix well to coat with spices. Cook for 5-7 minutes, stirring occasionally, until the mixture is well combined and slightly dry.

Remove from heat and stir in fresh cilantro. Let the filling cool completely before assembling samosas. Taste and adjust seasoning as needed.

Divide the rested dough into 10 equal portions and roll each into a ball. On a lightly floured surface, roll each ball into a 6-inch (15cm) circle, about 1/8-inch thick.

Cut each circle in half to create semicircles. Take one semicircle and form a cone by bringing the straight edges together, overlapping them slightly. Seal the seam with a few drops of water and press firmly.

Hold the cone in your palm and fill it with 1-2 tablespoons of cooled filling, leaving about 1/2 inch space at the top. Do not overfill as this will make sealing difficult.

To seal, brush the open edges with water, then press and fold the edges together, creating a triangular shape. Press firmly along all seams to ensure they are completely sealed. Repeat with remaining dough and filling.

Heat 4 cups vegetable oil in a deep, heavy-bottomed pot to 325°F (165°C). Use a candy thermometer to monitor temperature accurately - this is crucial for achieving the perfect golden, crispy exterior.

Carefully lower 4-5 samosas into the hot oil using a slotted spoon. Do not overcrowd the pot as this will lower the oil temperature and result in soggy samosas.

Fry for 8-10 minutes, turning occasionally, until golden brown and crispy all over. The samosas should float to the surface and have a deep golden color when done.

Remove with a slotted spoon and drain on paper towels. Serve immediately while hot and crispy, accompanied by mint chutney or tamarind sauce.