Cook lasagne sheets according to packet instructions.
Add onion and mince to a pan and cook till browned. Season to taste. Stir in passata and herbs. Remove from heat.
In a clean pan, melt the cream cheese over medium heat. Gradually add milk, whilst stirring, till you have the consistency of white sauce.
Lightly grease a baking dish. Layer the bottom of the dish with three lasagne sheets. Cover with a layer of mince, then with three more lasagne sheets. Cover with cream cheese sauce, then the final three pasta sheets. Finally, top with the remaining mince and then end with the remaining cheese sauce.
Place in oven and cook for about 20 minutes, but make sure it doesn't dry out.