Soak the stale bun in water for roughly 5 minutes until softened, then squeeze out excess water.
In a dry pan over medium-high heat, roast the sesame seeds for 3-4 minutes, stirring occasionally, until golden brown. Transfer to a plate and set aside.
In a large bowl, combine the minced meat, egg, squeezed bun, roasted sesame seeds, sesame oil, finely chopped onion, chopped garlic, chopped ginger, red chilli strips, chopped parsley, mustard, and basil pesto. Season with salt, pepper, nutmeg, sweet paprika powder, and Tabasco to taste. Knead the mixture thoroughly by hand until well combined.
Taste the mixture — it should taste noticeably spicy as the flavor will mellow during cooking. If the mixture is too wet, add breadcrumbs 1 tablespoon at a time until firm.
Shape the mixture into balls of roughly equal size.
Heat 3 tablespoons of oil in a large pan over medium-high heat.
Fry the meatballs for 10-12 minutes, turning occasionally, until golden brown on all sides and cooked through (internal temperature 63 °C / 145 °F if using pork, 74 °C / 165 °F if using chicken).