Heat a dry skillet over medium heat. Add the peanuts and sesame seeds and toast gently, shaking the pan often, until the peanuts are golden and fragrant and the sesame seeds are lightly browned. Remove from the heat and allow to cool slightly. Roughly chop the peanuts, keeping some halves for texture.

Place the oil in a small saucepan and warm over medium-low heat for one to two minutes. Add the garlic, ginger, and shallot and cook gently, stirring often, until softened and aromatic but not browned, about two to three minutes.

Reduce the heat to very low. Stir in the chilli flakes and sugar and let them bloom in the oil for one to two minutes. Keep a close eye on the pan. The oil should be hot enough to release flavour, not so hot that the spices scorch.

Remove from the heat and stir through the toasted peanuts and sesame seeds. Add the soy sauce and a pinch of salt, mixing well so everything is evenly coated in the spiced oil.

Allow the chilli oil to cool completely in the saucepan before transferring to a clean jar with a tight-fitting lid. The oil will thicken slightly as it cools, and the flavour will continue to develop over the next twenty four hours. Store in a cool, dark place for up to two weeks.