Chop ingredients as much as you can and place them into a blender. Make sure your blender is powerful or it will have a hard time making smooth paste.
Pulse to blend all the ingredients until smooth paste forms. Scrape sides and bottom of the blender when needed.
Store the curry paste in an air-tight glass container with a lid, in the refrigerator for 4-5 days.
You can also freeze it to keep for several months! I love to make a double batch and portion it out into about 1/3-1/2 cup servings and freeze it. Make sure to freezer it in air-tight freezer bags or containers. To thaw, do it slowly in the refrigerator.
*Adjusting spice level: If you like it hot and spicy, stay within the spicy pepper range. Of course, you have to have the Thai chili peppers, but you can also add in serrano peppers or mild Thai long chili peppers.To make it milder, use fewer Thai chili peppers (stay in the 3-4 range for mild and go up to 8 for medium spice), and use milder additional peppers, like poblano, jalapeño, or other milder chili peppers of your region.Another way to make this paste milder is to remove the seeds and white membrane from the peppers.