Place all the sliced leeks in a pot of water and wash them thoroughly. Leave them in the water for 10 minutes and all the sand will sink to the bottom. Scoop the leeks out with your hand to a colander and discard the sandy water and fill up with fresh water and repeat again for another 2 times or until you think the leeks are clean. Place them in a colander to drain off excess water. Bring a large pot of water to a boil and then blanch the leeks in the water for about 10 minutes and then discard water and let them cool off. Squeeze out excess water when it's cool enough to handle
In a large mixing bowl, add in the blanched leeks and the rest of the ingredients. Stir to mix well, but don't over stir the batter too much
Preheat oven to 200 F. Preheat a medium to large non-stick pan. Add in about 1 Tbsp of cooking oil and swirl to coat the pan. When the oil is hot enough, scoop about 1 Tbsp of the batter onto the pan and slightly flatten it with spatula and let it cook for about 3 minutes on each side. My suggestion is to have a taste of it and add more salt to the uncooked batter if you think it's needed and continue cooking until all the batter is used. Keep the cooked pancakes in the oven by placing them on top of the wire rack/cooling rack set on baking sheet. Serve immediately with some sri racha sauce or sour cream or both !!