1-First Step: Gather and prep everything Start by washing and drying the Thai basil leaves well. This matters because extra water can make the pesto thin and dull. Measure out the cashew nuts, peanuts, garlic, chilli flakes, oil, salt or soy, rice wine vinegar, caster sugar, and lime juice before you begin. If you are toasting the nuts yourself, do it in a dry pan over medium heat for 2 to 3 minutes, just until they smell nutty. Let them cool for a few minutes before blending. Toasting gives the sauce a deeper flavor, but it is still tasty if you use ready-roasted nuts straight from the bag.

2-Second Step: Add the solid ingredients to the blender Place the Thai basil leaves, cashew nuts, peanuts, crushed garlic, chilli flakes, salt or soy sauce, rice wine vinegar, and caster sugar into a food processor or small blender. If you like a stronger garlic note, you can rub the garlic with the side of your knife first to release more of its flavor. Pulse a few times before adding the oil. This helps the blades catch the leaves and nuts evenly. Scrape down the sides if needed so everything gets chopped in a more even way.

3-Third Step: Stream in the oil With the blender running, slowly pour in the 60 milliliters of olive oil or sesame oil. Add it in a steady stream so the mixture emulsifies and turns glossy. If the pesto seems too thick, add a small splash of water or a little more oil, one teaspoon at a time. Keep blending until the sauce looks coarse or smooth, depending on the texture you want. Some people like a rustic pesto with small bits of nut and basil. Others prefer a silky sauce that coats noodles more evenly. Both are good, so go with your own taste.

4-Fourth Step: Add lime juice and taste Now squeeze in the juice from half a lime and blend again. Taste the pesto and check the balance. If it feels too sharp, add a tiny bit more sugar. If it needs more punch, add a little more lime juice or a small pinch of salt. This is the point where the sauce really turns into a Thai basil pesto sauce. The lime makes it bright, the vinegar adds lift, and the chilli flakes give it a gentle kick. If you want more heat, you can add a few extra flakes, but do it slowly so it does not overpower the herbs.

5-Final Step: Serve or store Use the pesto right away, or move it to a clean jar. It works beautifully tossed through noodles, spooned over rice bowls, spread inside wraps, or served with grilled chicken, shrimp, tofu, or roasted vegetables. For a simple meal, stir some into hot pasta and add a splash of cooking water to help it coat the noodles. If you are serving this for the first time, start with a small spoonful, then add more after tasting. Thai basil pesto is bold, so a little goes a long way.