Place the lemon juice, olive oil, chilli flakes, cumin, paprika, onion, sugar, salt and pepper in a bowl and mix well to combine. Add the pork, cover and refrigerate for 1 hour to marinate+. Preheat oven to 200ºC (390ºF). Place the pork on a wire rack in a baking dish lined with non-stick baking paper, reserving the marinade. Roast for 25–30 minutes or until cooked through. Set aside to cool.
Place the reserved marinade and chicken stock in a small saucepan over high heat and cook for 5–10 minutes or until thickened slightly. Set aside and allow to cool. Place the pork and sauce together in an airtight container and freeze for up to 3 months. To defrost, place on a tray in the fridge overnight. Cook to your liking.
+ You can place the pork and marinade in an airtight container and freeze at this stage if you prefer.