Step 1

For the dough: Whisk together the flour, ajawain, if using, and the salt. Add the oil and, using your hands, rub it into the flour mixture until fully incorporated. While stirring with a wooden spoon, gradually add the water, until a shaggy dough is formed. Transfer the dough to a work surface and knead until soft and pliable, about 3 minutes. Rub a little oil, about 1 teaspoon, over the dough, place on a plate and cover with a damp towel. Let the dough rest in the refrigerator for at least an hour or overnight.

Step 2

For the filling: Put the potatoes in a medium saucepan, cover with cold tap water by about 2 inches, and season with salt. Bring to a boil, lower the heat, and simmer until tender, about 10 minutes. Drain, transfer to a medium bowl and set aside to cool slightly. Using a fork, slightly smash the potatoes.

Step 3

Meanwhile, in a small food processor (mini-chopper), combine the onion, ginger, garlic, chiles, and 1 tablespoon water and puree to a paste.

Step 4

Heat the ghee in a large skillet over medium-high heat. Add the mustard and cumin seeds and cook, stirring constantly, until fragrant, about 30 seconds. Add the onion paste, salt, garam masala and turmeric and cook, stirring, until lightly browned, about 4 minutes. Add the potatoes and cook, stirring and mashing lightly with a wooden spoon, until hot, about 2 minutes. Stir in the peas. Remove from the heat and stir in the lemon juice, chopped cilantro and remaining 2 tablespoons water.

Step 5

To form the samosas: Divide the dough into 10 portions. Using your hands, roll each portion into a small ball. On a floured work surface, using a rolling pin, roll each ball into a 7-inch wide disc. Cut each disc in half.

Step 6

Set a small bowl of water beside you. Working with one dough semi-circle at a time, fold half of the straight edge up to the rounded side and wet its outside edge with a little water. Fold the other half up to form a cone, overlapping it with the other side by 1/4 inch. Press the edges together to form a seal. Hold the cone in one hand and fill it with about 1/4 cup of the potato filling. Slightly wet the inside of the rounded edge and fold it over the filling to enclose it. Press the edges together to seal. Repeat with the remaining dough and filling to make 20 samosas.

Step 7

In a large, wide heavy-bottomed pot, pour in the oil to a depth of about 2 inches. Place over medium heat, and heat until a deep-fry thermometer inserted in the oil registers 365 degrees F.

Step 8

Working in small batches, fry the samosas until golden brown and crispy, about 5 minutes. Using tongs, transfer to a paper towel-lined baking sheet to drain. Serve immediately with tamarind sauce or your favorite chutney.

Step 9

For the ghee: Melt the butter in a small saucepan over medium-high heat. Skim off any of the white foam that comes to the surface with a spoon (being careful not to scoop up any yellow fat from the butter) and discard. Lower the heat to medium and simmer until all of the water has evaporated and the white milk solids have browned in the bottom of the saucepan, about 8 minutes.

Step 10

Line a sieve with cheesecloth or a coffee filter and pour the butter through into a container. Discard the browned milk solids in the sieve or reserve for another use. Use now or store in the refrigerator for up to 1 week. Yield: about 2 cups