Brown the Beef: Heat the olive oil in a large frying pan or skillet over medium-high heat. Add the beef mince and break it apart with a wooden spoon. Cook for 6-8 minutes, stirring occasionally, until the meat is deeply browned and releases a rich, savoury aroma. You'll hear a satisfying sizzle as the moisture evaporates, and the colour should change from pink to a deep golden brown.

Sweat the Vegetables: Reduce the heat to medium. Add the diced onion and cook for 4-5 minutes until it turns translucent and softens. The onions will release a sweet, fragrant smell as they cook. Add the minced garlic and stir for 30 seconds until you smell its pungent aroma bloom.

Build the Sauce Base: Stir in the tomato purée, paprika, and mustard powder. Cook for 1 minute, stirring constantly. The tomato purée will darken slightly and the spices will become intensely aromatic. You'll see the mixture thicken and cling to the meat.

Add Liquids and Pasta: Pour in the beef stock and whole milk, scraping the bottom of the pan with your wooden spoon to lift any browned bits. This deglazing step captures all that flavour. Add the dried macaroni and stir well. Bring the mixture to a gentle simmer — you'll see small bubbles breaking the surface, not a rolling boil.

Simmer the Pasta: Cover the pan with a lid and reduce the heat to low. Let it cook for 12-15 minutes, stirring halfway through to prevent sticking. The liquid will gradually absorb, and the macaroni will swell and become tender. The sauce will thicken and look creamy rather than watery.

Finish with Cheese: Remove the lid and stir in the grated cheddar and mozzarella. Add the butter if using. Stir gently until the cheese is fully melted and the sauce is smooth and glossy. The colour will shift to a pale orange, and you'll see long, stretchy strands of cheese as you stir. Taste and season with salt and pepper.

Rest Before Serving: Remove the pan from the heat and let it sit for 5 minutes. This resting time allows the sauce to thicken further and the flavours to meld together. You'll notice the texture becomes creamier and more cohesive.