Prepare the Pasta Shells: Bring a large pot of salted water to a rolling boil over high heat. Add the jumbo pasta shells and cook according to package directions until al dente – they should be tender but still have a slight bite. This usually takes around 10-12 minutes. Once cooked, drain the shells thoroughly in a colander and rinse them with cold water to prevent sticking. Lay them out in a single layer on a baking tray or clean surface to cool slightly while you prepare the filling.

Sauté Aromatics and Brown the Mince: Heat the olive oil in a large frying pan or skillet over medium-high heat. Add the chopped onion and sauté for 3-4 minutes until it softens and turns translucent, releasing a sweet aroma. Stir in the minced garlic and cook for another minute until fragrant. Add the lean beef mince to the pan, breaking it up with your wooden spoon. Cook, stirring occasionally, until the mince is evenly browned all over and no pink remains. You'll notice a rich, savoury smell filling your kitchen. Drain any excess fat from the pan.

Create the Taco Filling: Stir the taco seasoning mix, 120ml water, ground cumin, and smoked paprika into the browned mince. Bring the mixture to a gentle simmer, then reduce the heat to low and let it cook for 5-7 minutes, allowing the flavours to meld and the liquid to be mostly absorbed. The mixture should thicken and become intensely fragrant with a rich, reddish-brown colour. Remove from the heat and stir in the softened cream cheese until it's fully melted and incorporated, creating a creamy, cohesive filling. Finally, fold in half of the grated mature Cheddar cheese and all of the Monterey Jack cheese until just combined.

Prepare the Sauce Base: Preheat your oven to 190°C (375°F / Gas Mark 5). In a medium bowl, combine the chopped tomatoes and beef or vegetable stock. Season with a pinch of salt and black pepper to taste. Pour about two-thirds of this tomato mixture into the bottom of your 9x13 inch baking dish, spreading it evenly to create a bed for the stuffed shells.

Stuff the Shells: Take each cooked pasta shell and carefully fill it with a generous amount of the cheesy taco mince mixture. I used to struggle with getting enough filling into the shells without tearing them, but after testing this recipe five times, I finally got it just right by using a small spoon and being gentle. Arrange the stuffed shells snugly in a single layer in the prepared baking dish on top of the tomato sauce. They should look plump and inviting, ready for baking.

Bake to Cheesy Perfection: Pour the remaining tomato sauce mixture evenly over the stuffed shells. Sprinkle the remaining half of the grated mature Cheddar cheese over the top, ensuring an even layer for maximum cheesiness. Cover the baking dish tightly with foil and bake for 20 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese is beautifully melted and bubbly, and the edges of the sauce are gently simmering. The kitchen will be filled with an amazing aroma of baked pasta and spices. Let the dish rest for 5-10 minutes before serving.