Mix the meal, egg and salt together, adding just enough water to make a moist dough that holds together. Set aside. Heat the oil in a skillet, add the onion and garlic, and stir-fry over moderate heat until light brown, about 3 min. Set aside. Take the potato and 1/2 C. each of any other 3 vegetables and blanch in boiling water for 5 minutes. Drain well. Add these to the pan with the onion and garlic and stir-fry over moderate heat for 3 minutes, to mix well. Add salt and pepper. Cool. Take 1 heaping T. of the dough and press it out on a flat surface into a 2 1/2 inch square. Put 1 T. of the vegetable mixture on the bottom half of the square and fold it over into a triangle. Prepare all the samoosi this way. Heat the oil in a wok or skillet and brown the turnovers over moderate heat for about 3 minutes.
Drain on paper towels. Serve warm. Makes about 20 turnovers.