I asked my mom how to make Kroeung. She said that I could find it at the store sold as "Mae Ploy Red Curry Paste". But, if I wanted to make it myself I would need to blend the following ingredients:

• Chopped lemongrass, 2-3 stems
• Kaffir Lime leaf, 1 tbsp chopped
• Salt 1 tbsp
• Tumeric 1 tbsp
• Galanga 1 tbsp
• Garlic 6 cloves
• 2 big Shallots
• Fish Sauce 1 tbsp or shrimp paste
• Red Pepper or Paprika

Source: None