Kroeung (Khmer lemongrass paste)

Step 1: Slice 6 lemongrass across the stalk into rounds as thin as you can manage, 1–2 mm. Shred 6 makrut lime leaves into fine threads with a sharp knife.

Step 2: Put the lemongrass and ½ tsp salt in a large mortar and pound hard for 3–4 minutes, until it turns into a damp, fluffy green mass with no whole rings left. The salt acts as grit and speeds this up.

Step 3: Add 1 oz fresh galangal, ⅔ oz fresh turmeric and the lime leaf threads and keep pounding for another 3 minutes, until the mixture is bright yellow and you can no longer see separate slices of galangal.

Step 4: Add 6 cloves garlic, 4 shallots and 1 tsp lime zest and pound for 2–3 minutes more, until you have a thick, moist, fragrant paste that holds together on the pestle. If you use a blender instead, add everything at once with 2 tbsp water and blitz, scraping down often, for 2 minutes. Common mistake: pouring in a lot of water to get the blender going; a watery kroeung spits in the pan and never fries properly. Add a spoonful at a time and stop the moment the blades catch.

Step 5: Pack the paste into a clean jar, press it flat and cover the surface with a thin film of oil. Keep it in the fridge for up to a week, or freeze it in 2-tablespoon portions in an ice-cube tray for up to 3 months.