Heat a large deep ovenproof frying pan over medium-high heat.
Add the oil and onion and cook for 5 minutes or until soft and golden.
Add the garlic and beef and cook for 6 minutes, stirring, until the beef is well browned.
Add the stock, tomatoes, oregano, salt and pepper and bring to the boil.
Reduce the heat to medium and simmer for 35–40 minutes or until the mixture has reduced by roughly one-third.
Add the lasagne sheets, a few at a time, and gently stir to combine.
Cook, stirring occasionally, for 3 minutes or until the pasta softens.
Remove from the heat and stir through the basil.
Preheat oven grill (broiler) to high.
To make the mascarpone cheese topping, combine the mascarpone, parmesan and pepper.
Top the lasagne with small spoonfuls of mascarpone mixture and mozzarella.
Grill for 10–12 minutes or until the lasagne is golden and bubbly.
Finish with extra basil and parmesan to serve.
