Preheat your oven to 190°C (fan) — gas mark 5. While it heats, set your largest ovenproof skillet or a separate frying pan over a medium-high flame. You’ll know the pan is ready when a drop of water sizzles and evaporates instantly.

Brown the beef mince. Add the olive oil to the hot pan, then tip in the beef. Break it apart with a wooden spoon and let it sit undisturbed for a full minute — you want a deep, brown crust to form. Stir and repeat until the mince is evenly browned and no pink remains. The kitchen should smell rich and savoury, and the mince will look dark golden rather than grey.

Sweat the onion and garlic. Push the beef to one side of the pan. Add the diced onion and cook for 3–4 minutes, stirring occasionally, until it turns translucent and the edges begin to catch a little colour. Stir in the minced garlic and cook for another 30 seconds until it becomes fragrant — that sharp, pungent aroma tells you it’s ready.

Build the marinara sauce. Pour the passata into the pan and add the tomato purée, dried oregano, dried basil, salt, and black pepper. Stir everything together, scraping the bottom of the pan to lift any browned bits — those little flecks carry enormous flavour. Let the sauce come to a gentle simmer, then reduce the heat to low. You’ll see small bubbles breaking the surface and the sauce will thicken slightly, turning a deeper red as it cooks.

Combine the tortellini and half the cheese. Tip the entire bag of fresh tortellini into the pan and stir well to coat each piece in the sauce. The pasta will look pale and raw at this stage, which is exactly right. Sprinkle in half of the grated mozzarella and half of the Parmesan, then fold everything together until the cheese starts to melt into the sauce, creating a creamy, stringy texture.

Transfer to the baking dish. Pour the mixture into a 9x13 inch baking dish and spread it into an even layer. Scatter the remaining mozzarella and Parmesan over the top, covering the surface completely. The dish should look generous and slightly messy — that’s part of its charm.

Bake until bubbly and golden. Place the dish on the middle rack of the oven and bake for 20–25 minutes. After about 15 minutes, the sauce will be bubbling vigorously around the edges and you’ll hear a gentle hiss. In the final 5 minutes, the cheese on top will turn a patchy golden brown and the tortellini will puff up slightly. If you want a deeper crust, switch the oven to grill for the last 2 minutes and watch it closely — the cheese can go from golden to burnt in seconds.

Rest before serving. Remove the dish from the oven and let it sit on the counter for 5 minutes. This brief rest allows the sauce to settle and thicken, so your serving spoon doesn’t drag a watery streak across the plate. The tortellini will be tender but still hold their shape, and the cheese will stretch in long, satisfying ribbons when you lift a portion.