Sauté the aromatics: Heat the olive oil in a large frying pan or skillet over a medium-high heat. Add the diced onion and green bell pepper. Cook for 4–5 minutes, stirring occasionally, until the onion turns translucent and the pepper softens. You will notice a sweet, fragrant aroma filling your kitchen.

Brown the mince: Add the beef mince to the pan, breaking it up with a wooden spoon. Cook for 5–6 minutes, stirring frequently, until the meat is no longer pink and has started to brown. The sizzling sound will become more pronounced as the moisture evaporates, and you will see the mince turning a rich, golden colour.

Add the garlic and tomato purée: Stir in the minced garlic and tomato purée. Cook for 1 minute, until the garlic becomes fragrant and the tomato purée darkens slightly in colour.

Build the sauce: Pour in the chopped tomatoes, ketchup, brown sugar, Worcestershire sauce, smoked paprika, mustard powder, and cayenne pepper (if using). Stir everything together well. The mixture will look a little loose at this stage, with a deep red hue.

Simmer to perfection: Bring the sauce to a gentle bubble, then reduce the heat to low. Let it simmer uncovered for 10–12 minutes, stirring occasionally. As it cooks, the sauce will thicken and the flavours will meld together. You will see the mixture become glossy and cohesive, no longer watery.

Season and serve: Taste the filling and season with salt and black pepper as needed. Spoon a generous amount of the hot, saucy beef mixture onto the bottom half of each toasted bun. Top with the other half of the bun and serve immediately.