Brown the Mince: Heat the olive oil in a large frying pan or skillet over a medium heat. Add the chopped onion and cook for 5-7 minutes until softened and translucent. Add the minced garlic and cook for another minute until fragrant.

Cook the Sauce: Add the beef mince to the pan, breaking it up with a wooden spoon. Cook until it's browned all over. Drain off any excess fat. Stir in the passata, chopped tomatoes, oregano, basil, and the optional sugar. Season well with salt and pepper. Bring the sauce to a gentle simmer and let it cook for 5 minutes.

Prepare the Cheese Mixture: While the sauce is simmering, grab a medium bowl. Combine the ricotta cheese, most of the grated Parmesan (save a little for the top), the beaten egg, and the chopped fresh parsley. Mix until everything is well combined and season with a pinch of salt and pepper.

Begin Layering: Now for the assembly. What works best for me is to start with a thin layer of meat sauce on the bottom of your 6-litre (or larger) slow cooker pot. This prevents the ravioli from sticking.

First Ravioli Layer: Arrange a single layer of frozen ravioli over the sauce. It's okay if they overlap slightly.

Add Cheese and Sauce: Dollop about half of the ricotta mixture over the ravioli, spreading it out gently. Top this with about a third of the remaining meat sauce, followed by a third of the grated mozzarella.

Repeat the Layers: Create a second layer with the remaining frozen ravioli, the rest of the ricotta mixture, another third of the meat sauce, and another third of the mozzarella.

Final Topping: Finish with a final layer of the remaining meat sauce, ensuring all the ravioli are covered. Sprinkle the rest of the mozzarella and the reserved Parmesan cheese evenly over the top.

Slow Cook: Secure the lid on the crockpot and cook on the LOW setting for 3 to 4 hours. The lasagna is ready when the sauce is bubbling around the edges and the cheese is completely melted and golden.

Rest and Serve: Turn off the slow cooker and let the lasagna rest with the lid off for at least 15-20 minutes before serving. This step is crucial for letting the layers set, making it much easier to slice and serve. Garnish with a little fresh parsley if you like.