Clean and cut the chicken into small pieces (if you are using boneless chicken). Blend green chilies and garlic into a paste. Mix ginger-garlic paste and blended green chillies and garlic with the chicken. Marinate for 1 - 2 hours.
Heat oil in a pan, over a medium fire, add marinated chicken and cook for about 10 minutes. Ensure that the meat is tender and juicy. Set aside and let cool.
Meanwhile, boil potatoes. Let cool and mash them. Set aside.
When the chicken cools down, shred it into small pieces (if you are not using minced chicken).
Heat oil in a pan over medium fire. Add cumin seeds and onion. Saute until onion turns golden brown. Then add curry leaves, carrots and peas. Once the carrots and peas have cooked, add mashed potatoes, turmeric powder, red chilli powder, black pepper powder and salt. Mix well. Keep stirring to avoid the mix from sticking to the base. Set aside and let cool before using it for filling.
P.S. Decrease or increase the amount of red chilli powder and black pepper powder according to your preference.
For Samosa Wrapper: This is optional. You can choose to buy the ready-made samosa wrappers. However, below are the steps on how to make the traditionally handmade samosa wrappers.
First, mix together all purpose flour, semolina and salt. Then, add oil / butter to the flour and mix it well.
Add water in small amount and make dough out of it. Slightly wet your hands to easily knead the dough.
Once the dough is soft and pliable, knead it for another 5 minutes. Then wrap it with a plastic wrap or a damp clean cloth and let it rest for 20 to 30 minutes.
Divide the dough into 4 equal parts and shape them into balls. Roll each ball into 8 or 10 inch diameter circles and cut each circle into semicircles.
Hold one side of the semicircle and place it over the mixture. Then hold the other side of the semicircle and place it on top of the previous one, covering the mixture completely, forming a triangle.
The two sides of the triangle should be sticking together now, while the third side of it remains open. Now, wet your finger and rub it along the third side and close the gap.