Step 1: In a large mixing bowl, combine 2 cups all-purpose flour, 1/2 teaspoon salt, and 1/4 teaspoon carom seeds (ajwain). Mix well.
Step 2: Add 1/4 cup ghee or vegetable oil to the flour mixture. Using your fingertips, rub the fat into the flour until it resembles coarse crumbs.
Step 3: Gradually add about 1/2 to 3/4 cup cold water, a tablespoon at a time, and knead to form a firm, yet pliable dough. Cover the dough with a damp cloth and let it rest for at least 30 minutes.
Step 4: Boil 3-4 medium potatoes until tender but not mushy. Peel and roughly mash them.
Step 5: In a large pan or kadai, heat 2 tablespoons of oil over medium heat. Add 1 teaspoon cumin seeds and let them splutter. Then add 1/2 inch grated ginger, 1-2 finely chopped green chilies, and 1/2 cup green peas. Sauté for 2-3 minutes.
Step 6: Add the mashed potatoes to the pan. Season with 1 teaspoon salt, 1 teaspoon coriander powder, 1/2 teaspoon turmeric powder, 1/2 teaspoon garam masala, and 1/2 teaspoon dried mango powder (amchur). Mix everything thoroughly. Cook for 5-7 minutes, stirring occasionally, until the mixture is relatively dry. Let the filling cool completely.
Step 7: Divide the rested dough into 8-10 equal portions. Roll each portion into an oval shape, about 6-7 inches long and 4-5 inches wide.
Step 8: Cut the oval in half lengthwise, creating two semi-circles. Take one semi-circle and moisten the straight edge with a little water.
Step 9: Bring the two ends of the straight edge together, overlapping them slightly to form a cone. Press the seam firmly to seal it.
Step 10: Fill the cone with about 1.5-2 tablespoons of the cooled potato filling. Don't overfill.
Step 11: Moisten the top edges of the cone with water. Gently pinch and pleat the top edge on one side, then press the edges together to seal the samosa into its classic triangular shape. Make sure all seams are tightly sealed. Repeat with the remaining dough and filling.
Step 12: Heat enough vegetable oil for deep frying in a deep pan or wok over medium-low heat (280-300°F / 135-150°C).
Step 13: Gently slide 4-5 samosas into the hot oil, ensuring not to overcrowd the pan. Fry on medium-low heat, turning occasionally, until they are golden brown and crispy on all sides (10-15 minutes per batch).
Step 14: Remove the fried samosas with a slotted spoon and place them on a wire rack lined with paper towels to drain excess oil. Serve hot with your favorite chutney.