Add cold water and mix thoroughly (I like to use my hands). Start with 4 tbsp and continue to add 1 tbsp at a time until the mixture starts to become sticky. Do not add too much water at once, there is a fine line between a crumbly mixture and a sticky/gooey mixture.
Knead to a firm dough. Cover the dough with a moistened towel and set aside.
Place diced potatoes in boiling pot of water and cook until tender. Once cooked, strain water and set aside.
Sauté onion, garlic and ginger until cooked/onions are translucent.
Add curry paste to pan; cook for 2 minutes.
Add cooked potatoes to pan, cook for 2-3 more minutes.
Add frozen peas and carrots – cover mixture and let cook for 5-10 minutes until peas/carrots are thawed and hot.
Remove potato mixture from heat and leave to cool.
Divide dough into 1.5 inch diameter balls (8-10 balls). Use a rolling pin, roll balls into a flat circle. You want it just thick/strong enough to hold the filling. Cut the circle in half with a knife or pizza cutter.
Rub cold water with a brush (or finger) around the edge of the semi circle. Roll dough into a cone. Stuff the mixture into the cone and pinch closed. Repeat until complete.
Heat oil in a pan. Check that oil is hot by adding a small piece of pastry. Cook samosas until golden brown.
Once cooked, place samosas onto a paper towel to drain any excess oil.