Deseed dry chilies and soak it in hot water to soften for 20 minutes.
Meanwhile roast coriander seeds, cumin and pepper on low heat until aromatic for 2 minutes.
Let it cool completely before grinding.
Drain out chillies from the water.
Grind the dry spices and kaffir lime leaves.
Add shallots, chilies and pulse them few times
Add ginger, garlic, lemon grass paste, lemon zest , salt and cilantro leaves and grind until smooth.
The paste is now ready to use.
It will be very spicy and tangy , but balances out once added to the food.
Notes
This recipe makes around ¾ cup curry paste good enough for using 5-6 times.You may double the recipe to freeze.
Possible substitutes
Sometimes traditional Thai ingredients are hard to find.Swap ginger for galangal. Swap shallots for white onion. Substitute Kaffir lime leaves with fresh lemon juice Use lemon grass paste instead of lemon grass stalk for the same amount that is called for.
Storing curry paste
Red curry paste stays well in the fridge upto a week.You may store it in the freezer for 3 months. I freeze the paste in form of ice cubes.1 tablespoon measure , once frozen pop them out and place it in a freezer safe zip lock bag for future use .