To prepare the dough, mix the flour, salt, and ajwain seeds together in a medium bowl. Make a well in the center, and add the cultured coconut milk or yogurt. Mix together to form a dough. Add extra flour if needed, to keep the dough from being sticky. Tightly wrap and refrigerate until you are ready to assemble the samosas.
To prepare the filling, peel potatoes and dice into 1/4 inch cubes. Place in a saucepan, cover with water, and boil until very soft. Drain and set aside. Some people like to mash their potatoes at this point. It facilitates the process of filling the samosas, but I find that if I dice them small enough, I don't need to mash. But either way is fine.
Heat oil in a nonstick skillet on medium-high heat. Add mustard and cumin seeds and stir fry for about 30 seconds until cumin turns darker brown and mustard seeds begin to pop. Add onions, garlic, ginger, and green chiles (if using) and saute over medium heat for about 8-10 minutes, or until onions are soft. Add the peas, potatoes, raisins, water, coriander, salt, garam masala, and lemon juice. Cover, reduce heat to medium, and cook for 3-4 minutes. Add cashews and cook for 1-2 minutes more. Remove from heat, uncover, and allow to cool.
Preheat oven to 400 degrees.
To assemble the samosas, turn the dough onto a lightly floured surface and knead for 2-3 minutes until it is smooth and soft. Divide dough into 10 equal portions. Roll each portion between your hands to form smooth balls. Pour 1/4 cup water into a small bowl and set aside.
Roll each ball into a 6-inch circle and cut in half. Take one half, dip your finger into water, and run it along the straight edge. Fold in half, overlapping on end about 1/4 inch over the other, making a cone. Press to seal.
Fill the cone with potato filling. Dip finger in water and run along the inside of the cone mouth and press the lips together to seal. Place each samosa as it is made on greased cookie sheet or silpat. Brush each samosa with coconut or vegetable oil.* Although non-traditional, I like to use coconut oil, for that little extra flavor dimension and wonderful aroma. Bake for 12-15 minutes, then turn the oven down to 350 degrees F, turn the samosas over, brush the remaining sides with oil, and bake for 8-10 minutes more, until samosas are golden brown.
When samosas are done, serve immediately with mint or tamarind chutney.