Place flour, salt and oil in a bowl. Rub with your fingers, like pastry flour. It should look like bread crumbs. Make a firm dough adding a little water at a time, knead it well. Keep aside for 20 minutes, covered with a moist cloth and then knead again.
Making the Filling:
Heat oil in a pan. Add onion, ginger and green chillies and fry until onions are golden brown. Add meat and stir fry until meat is nicely browned. Add spices and stir fry for a few more minutes and add peas. Turn heat to medium and cook covered until meat is tender and all water is absorbed. Filling should be quite dry. You can turn the heat up towards the end and make sure all water has dried. Adjust spices if necessary. Turn heat off and allow to cool. Add coriander leaves and mix well. Allow to cool completely.
Mix 1 tsp. flour with 2 tbs. water, to make a 'glue'. Keep it aside.
Divide the dough into 8-10 portions and make balls, using greased hands. Keep covered with a moist muslin/cloth. Roll one ball on a greased surface, into an 7-8 inch circle, 2-3 mm. thick. Cut it into half using a knife. Lift one half in your palm and mak a cone, by folding the straight edge in the centre and overlapping. Glue the overlapping edges and press gently to give a good seal. Now fill the cone with approximately 2 tbs. of the meat mix. You should have enough edge left at the top, to get a good seal. Using the 'glue', press and seal edges together. Make all samosas like this. Keep them covered with a moist cloth. If pastry is allowed to dry, it is more likely to burst during frying.
Heat oil in a frying pan, on medium heat. Put as many samosa as will spread out easily in frying pan and fry gently to golden brown. Take out and place on kitchen paper, to absorb surplus oil.
Serve hot with Tomato Ketchup.