For the caramel spiced nuts, preheat the oven to 180C/350F/Gas 4 and line a baking tray with baking parchment.
Place the egg white in a large bowl and whisk until foamy. Add the rest of the ingredients and mix. Pour onto the prepared baking tray and bake for 15-20 minutes, or until the nuts are crisp. Set aside to cool before serving.
For the peanut butter chicken thighs, mix the soy sauce, rum and cornflour in a bowl. Add the chicken and mix well to ensure all the chicken is coated in the marinade. Leave to stand at room temperature for 10 minutes.
For the sauce, in a bowl, combine the vinegar, peanut butter, soy sauce, sesame oil and Sichuan peppercorns and mix until smooth.
Heat a wok or large heavy-based pan over a high heat. Add the peanut oil and swirl to coat the base. Add the chillies and stir-fry for about 30 seconds, or until the chillies have just begun to blacken and the oil is slightly fragrant.
Add the marinated chicken and stir-fry until opaque and cooked through – approximately three minutes.
Add the white parts of the spring onions, the garlic and ginger and stir-fry for about 30 seconds. Pour in the peanut butter mixture and coat the other ingredients. Stir in the peanuts and cook for another 1–2 minutes.
Serve the chicken and sauce on plates with steamed rice, sprinkling over the green parts of the spring onion and the spiced nuts at the end.